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Biomedical subjects

R H Gray

Publications and source records attributed to R H Gray.

At least 127 records · Page 7Linked to original sources
PubMed1990

Time trends in risk factors and clinical outcome of ectopic pregnancy.

Ectopic pregnancy (EP) admissions at The Johns Hopkins Hospital were reviewed for 160 patients admitted from 1970 to 1974 and 253 patients from 1980 to 1984. Over the decade, average annual admissions for EP increased by 64%, and a higher proportion of cases in 1980 to 1984 were unmarried women with no insurance coverage. There were significant increases in cases with a history of sexually transmitted diseases (from 19.1% to 31.6%) and in recurrent EPs (7.6% to 19.0%) but declines in EP associated with contraceptive failures. Newer diagnostic techniques such as quantitative serum human chorionic gonadotropin assays, pelvic ultrasound, and laparoscopy were more frequently used in the 1980 to 1984 period, resulting in less severe morbidity on admission, more conservative surgical management, and reduced length of hospitalization. Thus, although admissions for EP have increased, the severity of illness has been reduced by earlier diagnosis and more conservative management.

Adult↗
PubMed1989

Interobserver variation in estimation of day of conception intercourse using selected natural family planning charts.

In order to study outcome of pregnancy related to timing of conception it is necessary to have both markers of ovulation and records of intercourse. Natural family planning (NFP) charts where the woman records basal body temperature (BBT) and mucus signs are ideal for this purpose. Much work has been done relating timing of BBT and mucus signs to ovulation, but very little work has been done to examine interobserver agreement on the interpretation of these signs. Four NFP experts examined 28 NFP pregnancy charts to determine the BBT rise, the mucus peak, and two most likely days of conception intercourse. The charts were selected because they provided difficulties in interpretation. The reviewers were able to agree on the most probable day of conception intercourse in 96.4% of cases, on the mucus peak in 74.1% of cases, and on the interval between the most probable conception intercourse and mucus peak in 70.4% of cases. There was poor agreement on the first day of the BBT rise (38.5%). The authors conclude that in selected difficult NFP charts, the mucus peak is a more valid indirect measure of ovulation both because it is subject to less interobserver variation and because it more closely approximates the timing of ovulation.

Body Temperature↗
PubMed1989

Retinal detachment and its relation to cataract surgery.

In Western Australia during the period 1 January 1976 to 31 December 1987 1089 eyes of 1044 patients in hospital were operated upon for primary rhegmatogenous retinal detachment due to causes other than penetrating trauma. Of these eyes 295 (27%) were aphakic or pseudophakic. During this period the annual number of cataract operations in the State increased by a factor of 245%, while aphakic and pseudophakic retinal detachment operations rose by only 55%. The declining risk of retinal detachment following cataract surgery is attributed to improvements in microsurgical techniques. In 1983 and 1984 the incidence of aphakic and pseudophakic retinal detachments dropped significantly (p less than 0.05). At about this time extracapsular cataract surgery became widespread in the State, and this may explain the observed fall in retinal detachment operations. Since 1984 the incidence has risen owing to the rapidly increasing prevalence of pseudophakia in the resident population.

Adult↗
PubMed1989

Fluorescein angiographic findings in three patients with long-term intravitreal liquid silicone.

The long-term retinal effects of intravitreal liquid silicone (ILS) remain controversial. In this study fundus fluorescein angiographic findings in three patients with long-term ILS are presented. Sluggish or absent blood flow was observed in retinal arterioles that lay in close proximity to the ILS, and the arterioles themselves appeared narrowed. It is suggested that ILS may have a long-term effect on the retinal vasculature, owing either to direct vascular damage, secondary to damage to the neuroretina, or to the ILS preventing diffusion of oxygen into the vitreous cavity.

Adult↗
PubMed1989

Efficacy of Nd-YAG laser iridotomies in acute angle closure glaucoma.

Between September 1984 and April 1987 a total of 150 patients underwent Nd-YAG laser iridotomy procedures at the Bristol Eye Hospital. Forty of these patients (27%) were treated for acute angle closure glaucoma (AACG), and three of them (7%) suffered recurrent AACG. Sixteen patients who had been treated for AACG have been challenged by a pharmacological provocative test introduced by Mapstone, with a total of 23 eyes being tested. A negative result was obtained in all cases. Provocative testing is recommended to help identify those at risk of recurrent AACG.

Glaucoma↗
PubMed1988

Steroid contraceptive use and pregnancy outcome.

Contraceptive use in relation to pregnancy outcome was studied in 8,816 births in Chiang Mai, northern Thailand, by examination of newborn infants and interviews with their mothers. Four thousand twenty-three women used no contraception before the index pregnancy, 1,229 used the injectable contraceptive Depo Provera (DMPA), and 3,038 used oral contraceptives prior to or during pregnancy. No differences were observed between these groups with respect to still births, multiple pregnancies, and birthweight. Women who used oral contraceptives had unexpectedly low rates of major defects and may have been affected by self-selection bias, whereas the noncontraceptors had rates similar to other populations. There was a significantly increased association of polysyndactyly among infants of DMPA users relative to the other groups, which was most pronounced in offspring of women under age 30 years, and persisted after exclusion of subjects with a family history or infants with multiple abnormalities. However, in five out of the ten polysyndactyly cases, the last injection of DMPA occurred more than 9 months before conception, and only three cases had definite gestational exposure. The association of chromosomal anomalies was also significantly increased in infants of mothers who used DMPA. The unrelated nature of these defects, the lack of confirmation from other studies, the distant preconceptional exposure to DMPA in many cases, and chance effects due to multiple statistical comparisons make a causal association unlikely. Other birth defects that had been previously reported in some publications to be associated with progestational steroid exposure, such as neural tube defects, heart malformations, and limb reduction defects, were not found in this study.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Drug-Induced↗
PubMed1988

Pregnancy outcome associated with natural family planning (NFP): scientific basis and experimental design for an international cohort study.

Although natural family planning (NFP) is a form of contraception without ostensible maternal risks (other than pregnancy), potential fetal risks could exist if aging gametes are involved in inadvertent fertilization. In the following report, we first review animal studies firmly establishing that aging sperm and aging oocytes (delayed fertilization) cause chromosomal abnormalities in mammals and other species. We next review human studies associating decreased coital frequency with trisomy and studies of NFP populations that generally show no increased frequency of anomalous offspring or spontaneous abortions. Our rationale for initiating an international cohort study is presented, along with the experimental design selected. Preliminary findings indicate that the experimental design chosen will indeed provide information allowing NFP safety to be assessed definitively.

Aging↗
PubMed1988

Induction of hepatic aryl hydrocarbon hydroxylase activity in rainbow trout (Salmo gairdneri) exposed to coal liquids.

1. The hepatotoxic response of rainbow trout (Salmo gairdneri) to a middle distillate (MD) and heavy distillate (HD) coal liquid was determined following administration by injection or in food. Hepatic aryl hydrocarbon hydroxylase (AHH) activity was compared to the known AHH inducer, benzo(a)pyrene. 2. Acute toxicities (LD50) of 1500 and 1410 mg/kg were obtained 120 hr after intraperitoneal injection (i.p.) for MD and HD coal liquids, respectively. Only the HD induced AHH activity when injected at 5% and 10% of the acute LD50. 3. Ingestion of 7 or 70 mg HD/kg body weight for 1 week resulted in AHH induction at 5-7 times that of control values. Levels of hepatic AHH activity in fish treated at 7 mg HD/kg declined to 2.6 times control values 7 days after exposure. Maximum induction was observed for the 70 mg HD/kg group that was provided control food for 1 week following 2 weeks of exposure. 4. The hepatic index (HI) or liver to body weight ratio generally increased along with increased activity in the enzyme response system.

Animals↗
PubMed1988

Interpregnancy interval and low birth weight: findings from a case-control study.

In a case-control study in Natal, northeast Brazil, conducted between September 1984 and February 1986, 303 cases of intrauterine growth retardation and 282 cases of preterm delivery were compared with 1,710 normal controls to ascertain the effects of the preceding birth-to-conception interval on pregnancy outcome. The risk of intrauterine growth retardation associated with interpregnancy intervals of six months or less was 1.38 (95% confidence interval (CI): 1.02-1.86) after adjustment for maternal age, education, smoking, and prior fetal loss or low birth weight. When maternal postpartum body weight was introduced into the logistic model, the risk of intrauterine growth retardation decreased slightly to 1.25 and was no longer significant (95% CI: 0.91-1.72). Short interpregnancy intervals (six months or less) were more frequently observed in women with postpartum body weight of less than 45 kg (31.1%) than in women weighing 50 kg or more (18.9%), which might suggest that the effect of short intervals on the risk of intrauterine growth retardation is mediated through maternal nutritional status. No association was found between birth-to-conception intervals and preterm delivery.

Adult↗
PubMed1988

Epidemiological studies of natural family planning.

The prevalence of the use of natural family planning (NFP) can be estimated from sample surveys of married women in the reproductive ages (MWRA). Surveys in developed and developing countries during the past decade indicate that the prevalence of NFP use varies from 0 to 11%. In addition, if one considers NFP use in relation to other contraceptive methods, the percentage of all current contraceptors who use NFP varies from 1 to 35%. This suggests that NFP is an important method in certain countries. Pregnancy rates for NFP vary widely, but most reliable studies report 1-year life-table pregnancy rates between 10 and 25/100 woman-years. The Billings ovulation method consistently has higher pregnancy rates than the sympto-thermal method and NFP users generally have among the highest pregnancy rates compared to other methods. The major safety issue concerning NFP is the risk of adverse pregnancy outcomes associated with aged gametes. There are suggestions from a number of investigations that conceptions distant from ovulation have a higher risk of spontaneous abortion and a higher proportion of male births. The findings with respect to birth defects or multiple pregnancies are less consistent, although some studies have reported an increased risk of chromosomal anomalies.

Abortion, Spontaneous↗
PubMed1988

Analysis of the outcome of 124 pregnancies produced during NFP.

The outcome of 124 pregnancies produced during the use of CM (Billings) of NFP is analyzed. The spontaneous abortion rate was 8%. The women who became pregnant in the less fertile period (+/- 3 days from peak day) presented a higher rate of spontaneous abortions (13.9%) than the women who became pregnant during the most fertile period (peak day +/- 2 days), who presented a 4.3% spontaneous abortion rate. Among the 115 living infants (one twin pregnancy) there was one congenital malformation (0.8%), a cleft palate. The sex ratio of the infants was 0.59 (48 females and 67 males), which is not significantly different from the 0.51 sex ratio expected. When conception occurred during the most fertile period, the sex ratio was 0.37, in contrast to the sex ratio of 0.76 when conception occurred in the less fertile period; this is a highly significant difference (P less than 01).

Abortion, Spontaneous↗
PubMed1987

Deficiency of inducible suppressor cell activity in the Chediak-Higashi syndrome.

Peripheral blood lymphocytes from two Chediak-Higashi syndrome (CHS) patients were examined for their 1) natural killer (NK) cell functions 2) concanavalin A (Con A)-inducible suppressor cell activity, 3) soluble suppressor factor production, and 4) responsiveness to interferon alpha and interleukin-2 in comparison with age-matched normal controls. Peripheral blood lymphocytes or NK-enriched large granular lymphocytes from Chediak-Higashi syndrome patients showed negligible cytotoxic activity against several target cells. Although the NK activity of Chediak-Higashi syndrome lymphocytes could not be restored to normal levels by treatment with either interferon or interleukin-2, the percent enhancement of NK activity was higher for the patients than the controls. Soluble suppressor factor activity of culture supernates from the lymphocytes of Chediak-Higashi syndrome patients significantly inhibited the NK activity of allogeneic, normal peripheral blood lymphocytes, whereas lymphocytes from Chediak-Higashi syndrome patients precultured with Con A failed to suppress the cytotoxic activity of normal lymphocytes. These results demonstrate a previously unrecognized suppressor cell dysfunction in CHS patients.

Chediak-Higashi Syndrome↗
PubMed1987

Identification of plasma cells in lung alveoli and interstitial tissues after localized lung immunization.

Large numbers of antibody-forming cells (AFC) can be identified with the Jerne plaque assay in immunized lung lobes of the beagle dog after localized instillation of particulate antigen. Published data suggest that these AFC are secreting antibody and are responsible for increased levels of specific antibody in immunized lung lobes. If AFC in the lung are actively secreting antibody, there should be an increase in the number of mature plasma cells in lung lobes exposed to antigen. The purposes of this study were to evaluate the number of lymphoid cells present in immunized and control lung lobes and to determine if lung immunization produces a localized increase in the number of plasma cells. Sheep red blood cells (SRBC), autologous dog red blood cells, and saline were instilled into specific lung lobes of beagle dogs with the aid of a fiberoptic bronchoscope. Light and transmission electron microscopy studies of tissues from lung lobes instilled with SRBC showed perivascular infiltrates and intra-alveolar accumulations of lymphoid cells which were not present in control lung lobes. The morphology of these lymphoid cells ranged from small lymphocytes through mature plasma cells. From 5% to 15% of the cells present in the interstitial tissues and alveoli of immunized lung lobes were plasma cells. These observations suggest that lymphoid cells which entered the SRBC immunized lung can mature to plasma cells which are probably responsible for the local production of antigen-specific antibody.

Animals↗