FAILURES OF THE MEMBRANE OF THE CONDOM

1) Permeability of the latex membrane for microparticles, STD agents and
HIV
In 1977 D.Barlow v advanced the hypothesis of the existence of some pores
in
the latex membrane of a condom in order to explain why this did not appear
to protect
against non-gonococcal urethrites and genital infections with Condylomata
acuminata.
This hypothesis has been revived in order to account for HIV infections
acquired during
sexual intercourse "protected" by use of a condomvi.
S.G.Arnold et al. (1988) vii have examined latex gloves from four
manufacturers using scanning electron microscopy and X-ray analysis.
They found that all of the gloves had pits 3-15µm wide and up to 30µm deep
on both interior and exterior surfaces. Irregular particles (30-50µm)
containing silicon and magnesium were embedded in the latex deeply enough
to cause pits themselves.
________
REF: -
Freeze-fractured
1 Pontifical Council for the Family, Rome. Current adress: 18 via della
Traspontina, Roma, 00193, Italy.
2 English translation by D.E.Parry from the revised original article « Le
"sexe sûr" et le préservatif face au défi du Sida», Medicina e Morale,
n°4, 1997, pp.689-726.
2 sections of all gloves showed cavities throughout the matrix and
tortuous channels
(5µm) penetrating the entire thickness of the glove.
_________
Such irregularities in latex membrane surface and structure do not seem to
be encountered in condoms, at least when they are new, and have not been
exposed to heat, oxygen, or ozone. However, under scanning electron
microscopy, the surface of a latex condom membrane is not uniformly
smooth: it appears made of smooth areas separated by puckers and dimples
scattered across the specimen (viii). There are hollows and irregular
projections on this surface, with irregular, dense inclusions (ix).
Although numerous pores are visible in scanning electron microscopy of
natural condoms (x,) no
evidence of breaks, fissures or pores have yet been reported in the few
published
transmission electron microscope studies of latex condoms (xi).
Some authorities have concluded that latex membranes of condoms, despite
their nonhomogeneous structure and the irregularity of their surface,
could be considered free of microscopic pores, of a size down to that of
the smaller virus.
However, these results have been put in question.
First, as Rosenzweig et al.(xviii) say it, all the aboved mentioned
electron microscopic studies of condoms have been "predominantly
anecdotal".
These later authors, in their own study of thirty samples from fifteen
non-lubricated Trojan condoms, did find that a large proportion of these
samples have visible surface abnormalities, with only 30% of all condoms
tested completely free of detectable defects under all magnifications. 50%
of the samples revealed a surface abnormality interpreted as either
cracking, melting or both.
Second, in vitro studies about the grade of impermeability of condoms
membranes to microorganisms, using a condom plunged into a culture medium,
are few, and limited to small sample sizes.
Confidence intervals constructed around reported failure rates indicate
that "true" permeability rates could be quite high, and
new data suggest that some condom do leak HIV and that leakage is not
necessarily
related to whether or not they are made of late (xxix).
Moreover, experience with STDs shows the need for prudence in
extrapolating results obtained in vitro to situations in (vivoxx).
Third, optimism about condoms membrane integrity has been shaken after
closely controlled condoms, coming from known manufacturers, had shown a
permeability to microspheres of greater size than that of HIV (6 condoms
out of 69)xxi.
Carey et al.(xxii) observed the passage of polystyrene microspheres, 110
nm diameter (
HIV diameter is from 90nm to 130 nm) across 33% of the membranes of the
latex
condoms which they studied (29 over 89 nonlubricated latex condoms).
More recently, Lytle et al., while criticizing the "exaggerated
conditions" of the in vitro, polystyrene microspheres test carried out by
Carey et al., found that 2,6% (12 of 470) of the latex condoms did allow
some virus penetration, with no difference between lubricated and
nonlubricated condoms (xxiii).
It has been said that since HIV in semen is associated with white blood
cells
(and, may be, also with spermatozoa) and since neither spermatozoa nor
white cells
can pass through these very small hypothetic "pores" in the latex, then
HIV itself cannot
pass. So these "pores", even if they do exist, could not therefore be of
such
importance.
But this is deceptive. In fact HIV is present in sperm in two forms:
associated with white blood cells and as free virus particles (xxiv); And
C.J.Miller et al. have demonstrated that cell-free virus preparations are
capable of producing HIV
infection by the genital route xxv.
Given their size, such free viruses from semen could transit through the
smallest defect of the membrane of a condom and reach, in the
organism of the sexual partnerxxvi, CD4 in Langerhans, lymphocytes and
macrophages
cells.
They may also potentiate indirectly the infectivity of HIV-1 in semen,
regardless of
HIV-1 source (xxvii).