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Biomedical subjects

A G Hunter

Publications and source records attributed to A G Hunter.

At least 19 recordsLinked to original sources
PubMed1992

Renal tubular dysgenesis: a not uncommon autosomal recessive syndrome: a review.

Renal tubular dysgenesis is a recently recognized autosomal recessive condition characterized by short and poorly developed proximal convoluted tubules, leading to oligohydramnios, Potter sequence, and neonatal respiratory failure. We report an additional 9 cases from one pediatric center, suggesting that this syndrome is not as rare as was previously thought. Normal amniotic fluid volumes in affected pregnancies prior to the 22nd week of gestation have been documented, compromising early prenatal diagnosis. Late second trimester sonographic demonstration of oligohydramnios, with structurally normal kidneys, should suggest this diagnosis and the need for detailed post-mortem pathological examination.

Female↗
PubMed1992

Evaluation of a TEST-yolk sperm capacitation system for use in bovine in vitro fertilization.

Bovine sperm acquire the ability to penetrate zona-free hamster oocytes (capacitation) after incubation in TEST-yolk buffer. Our objective was to determine whether such sperm could penetrate zona-intact bovine oocytes in vitro. Bovine cumulus enclosed oocytes from 2- to 5-mm follicles were incubated in maturation medium for 24 h at 37 degrees C. Ejaculated bovine semen was diluted 1: 10 in TEST-yolk buffer, cooled to 4 degrees C, and stored for 8 h to induce capacitation. Sperm were then washed thrice in pH 7.6, .15 M NaCl containing .1% bovine serum albumin V (37 degrees C) and diluted to 2 x 10(6) sperm/ml in fertilization medium. Droplets of fertilization medium containing capacitated sperm, killed sperm, or no sperm were made under paraffin oil. Oocytes (matured 24 h) were added and cocultured with sperm for 8 h and then transferred to fresh fertilization medium for 40 h. After 24 h, 53% of the oocytes had matured (metaphase II). The fertilization rate of the metaphase II oocytes (203) with TEST-yolk capacitated sperm was 87%, whereas the parthenogenetic controls were 2 and 0%, respectively. Therefore, TEST-yolk buffer can be used to capacitate bull sperm for in vitro fertilization.

Animals↗
PubMed1992

Identification of a receptor on the vitelline membrane of bovine oocytes that recognizes bovine immunoglobulin G.

In order to investigate whether Ig molecules affect bovine fertility, bovine follicular oocytes were tested for an oolemmal receptor that recognized IgG. The zona pellucida was removed from 296 oocytes. The zona-free oocytes were then incubated with purified bovine IgG. its Fc fragment, or its Fab fragment. They were subsequently washed and incubated with the appropriate rabbit antibovine IgG (whole IgG-specific, Fc-specific, or Fab-specific), which was covalently attached to polyacrylamide beads (immunobeads). Bead attachment was scored using light microscopy. Bovine IgG and bovine IgG-Fc bound to the oocytes, whereas the IgG-Fab exhibited negligible binding. The data indicate that a bovine oolemmal receptor exists that binds IgG by recognizing the molecule in the region of the Fc-Fab junction. Thus, the binding of IgG or other Ig molecules to bovine oocytes may play a role in sperm and egg interaction.

Animals↗
PubMed1991

Familial renal-hepatic-pancreatic dysplasia and Dandy-Walker cyst: a distinct syndrome?

Ivemark et al. first described sibs with renal-hepatic-pancreatic dysplasia (RHPD) (Ivemark BI, Oldfelt V, Zetterström R (1959): Acta Pediatr Scand 48: 1-11). Subsequent reports of affected individuals have described additional malformations and syndromes associated with RHPD. In this paper we describe 2 sibs with RHPD in association with Dandy-Walker cyst (DW). Through an examination of the pattern of associated malformations seen in RHPD we argue that RHPD-DW is a distinct monogenetic syndrome, and not an association.

Abnormalities, Multiple↗
PubMed1991

Distribution of Boophilus species ticks in Swaziland.

Recent outbreaks of bovine babesiosis caused by Babesia bovis in Swaziland had indicated the presence of the vector tick Boophilus microplus in the country although it had never before been directly identified. Engorged female Boophilus ticks were collected from cattle at diptanks in the course of a tick resistance survey and used to map the distribution of the two different species of Boophilus. B. decoloratus was found to be widespread throughout the country. B. microplus was identified for the first time in Swaziland and was found to have a patchy distribution. The implications of these findings are discussed.

Animals↗
PubMed1991

Atelosteogenesis I and boomerang dysplasia: a question of nosology.

We report a patient whose clinical, radiologic and histopathologic findings are compatible with severe atelosteogenesis (AT-I). The patient is compared with previously reported cases of AT-I, as well as with patients reported as having "boomerang" dysplasia. We conclude that it is reasonable to consider AT-I and boomerang dysplasia as part of a spectrum, probably reflecting a common etiology. More and detailed clinical, radiologic and histopathologic reports are needed to further clarify the relationship of AT-II and AT-III in this family of skeletal dysplasias.

Bone and Bones↗
PubMed1990

Apparent Smith-Lemli-Opitz syndrome in a child with a previously undescribed form of mucolipidosis not involving the neurons.

A diagnosis of Smith-Lemli-Opitz syndrome was made shortly after birth in a small-for-dates infant, on the basis of a characteristic face, penoscrotal hypospadias, bilateral postaxial hexadactyly, and bilateral syndactyly of toes 2-3. The clinical course was marked by failure to thrive, severe delay, refractory myoclonic jerks beginning at age 2 months, and increasing hepatosplenomegaly. He developed corneal clouding and increased gingival hypertrophy and died at age 18 weeks. Autopsy disclosed widespread storage of mucopolysaccharides and lipids within the macrophages and, to a lesser extent, parenchymal cells, of all organ systems. There was extensive demyelination of the cerebral white matter, and dystrophic calcification in the cerebrum, cerebellum, and brainstem. There was no evidence of primary neuronal involvement in the storage. Although the chance concurrence of 2 uncommon diseases is rare, a causal link between the clinical anomalies and the storage disorder cannot be argued convincingly on the basis of one case. Careful pathologic studies of other children who die with clinical signs compatible with Smith-Lemli-Opitz syndrome are indicated.

Brain↗
PubMed1990

Black grandmothers in multigenerational households: diversity in family structure and parenting involvement in the Woodlawn community.

We report here the frequency of black grandmothers' coresidence in households with first-grade children, their patterns of involvement in parenting, and the degree to which family structure and employment affected the grandmothers' parenting involvement in a 1966/1967 community-defined population. Coresidence between grandmothers and their target first-grade grandchildren was found in 10% of the households. The 130 grandmothers' parenting involvement was substantial, second only to mother involvement, and was characterized by 2 parenting activity patterns: control and punishment, and support and punishment. The degree of grandmothers' parenting involvement differed by family structure, with grandmothers in mother-absent homes most likely to be involved. Grandmothers' employment did not moderate their engagement in parenting behaviors. These findings are consistent with previous reports of significant parenting involvement by black extended family members.

Adult↗
PubMed1990

Effect of season on seminal traits and serum hormone concentrations in captive male Siberian tigers (Panthera tigris).

Electroejaculates and serum samples were collected throughout the year from 5 male Siberian tigers. Semen quality, seminal plasma chemistry and serum hormone concentrations were evaluated and analysed as a function of season. Semen volume, concentration, motility, viability and morphology were not influenced by season. The ability of spermatozoa to undergo capacitation and penetrate zona-free hamster eggs did not differ due to season. Season had no influence on seminal plasma concentrations of acid phosphatase, calcium, glucose, potassium and phosphorus. Serum values of thyroxine and triiodothyronine were lowest (P = 0.002 and P = 0.03, respectively) during the summer months while cortisol showed no seasonal variation. Serum testosterone concentrations were higher in fall and early winter (P less than 0.001) than at other times of the year but were not correlated with semen quality. These results demonstrate that season has no effect on the semen production and quality of captive male Siberian tigers.

Animals↗
PubMed1989

Growth and development in thanatophoric dysplasia.

Two cases of prolonged survival of thanatophoric dysplasia are presented, in which ventilatory support was initiated in the neonatal period because of respiratory distress. Both patients required a ventriculoperitoneal shunt for hydrocephalus and had decompression of the posterior fossa. The history of each patient has been characterized by profound developmental delay and dramatic growth failure.

Arm↗
PubMed1989

VACTERL with hydrocephalus: further delineation of the syndrome(s)

Central nervous system defects including hydrocephalus are rare in cases of VACTERL association. However, recent reports suggest that there may be one or more disorders in which this combination of anomalies occurs. We report 8 additional patients including a recurrence in a previously described family, review the literature, and provide some population-based data of VACTERL-type anomalies in hydrocephalus cases. VACTERL with hydrocephalus appears distinct from hydrolethalus and similar conditions but is itself heterogeneous. The pattern of inheritance of the disorders involved is unclear, but autosomal recessive and sex-linked forms likely occur. The prognosis of VACTERL cases with hydrocephalus appears much poorer than for those with classic VACTERL anomalies, and the recurrence risk may be higher than for either the VACTERL association or isolated hydrocephalus.

Abnormalities, Multiple↗
PubMed1989

A reordering of human chromosome 19 long-arm DNA markers and identification of markers flanking the myotonic dystrophy locus.

The gene for myotonic dystrophy (DM), the most common form of adult muscular dystrophy, has previously been mapped to the proximal long arm of chromosome 19. We have conducted linkage analysis on 53 DM families (comprising 421 individuals) using seven DM-linked DNA markers. This analysis, combined with our somatic cell hybrid mapping panel data, places the DM locus more distal on the chromosome 19 long arm than previously thought. Further, we have been able to unequivocally identify DNA markers that flank the disease locus. The definition of a 10-cM region of chromosome 19 that contains the DM locus should prove useful in both the search for the causative gene and the molecular diagnosis of DM.

Chromosome Mapping↗
PubMed1989

In-vitro induction of capacitation of fresh and frozen spermatozoa of the Siberian tiger (Panthera tigris).

Electroejaculates from 5 tigers were split and half of each was assayed fresh while the remainder was frozen and thawed before being assayed. Preincubation time, temperature and removal of seminal plasma were evaluated for their effect on in-vitro capacitation. Ability of spermatozoa to penetrate oocytes, as measured by the zona-free hamster egg-sperm penetration assay (SPA), was used as verification of capacitation. Results of the experiments with fresh semen indicate that: (1) preincubation time affects the fertilizability of tiger spermatozoa with 2 h appearing optimal, (2) a preincubation temperature of 37 degrees C results in significantly higher penetration rates than does a 22 degrees C treatment, and (3) tiger seminal plasma does not appear to contain decapacitation factors, as has been reported for several other species. Frozen semen experiments indicate that (1) frozen-thawed tiger spermatozoa must be removed from the environment of the semen extender before capacitation can take place, and (2) the freeze-thaw procedure results in a shortening of the required capacitation time.

Animals↗
PubMed1989

Induction of bovine sperm capacitation by TEST-yolk semen extender.

Ejaculated bull semen was diluted 1:10 in the TEST-yolk buffer, cooled slowly to 4 degrees C, and stored for up to 48 h. Aliquots were taken at 0, 4, 8, 16, 24, and 48 h and washed once or three times in bovine serum albumin-saline and the sperm pellets resuspended in this saline. Fertilization of zona-free hamster oocytes was used to assess sperm capacitation. Motility differed between samples washed once or three times (53.7 vs. 21.7%). Motility was highest at 4 h storage but did not differ between 16, 24, or 48 h of storage. More sperm without intact acrosomes were found at 4 h than at 0 h, but the percentage did not change further until after 24 h. Penetration of oocytes was not different between sperm washed once or three times (28.5 vs. 26.9%). No penetration occurred at 0 h, and highest penetration rates occurred at 4 and 8 h of storage (32.1 and 33.4%). Penetration rates at 16, 24, and 48 h were not different (25.3, 25.2, 22.5%). In conclusion, storage of bull sperm in TEST-yolk buffer for 4 to 48 h resulted in capacitation. Even though capacitation was induced by 4 h, at least 71% of the sperm population had not undergone an acrosome reaction by 48 h of storage. This may explain why penetrability was maintained over this period.

Acrosome↗
PubMed1989

Effect of washing and capacitating media pH on bull sperm motility, acrosome integrity, and ability to penetrate zona-free hamster oocytes.

Bovine-ejaculated sperm were washed thrice in bovine serum albumin-saline media, pH 7.2 to 8.4, and incubated at 37 degrees C in Ca++-free Tyrode's media. pH 7.2 to 8.4, for 0, 2, 4, 6, and 8 h. Motility was highest when sperm were washed in pH 7.2 medium and incubated in pH 8.0 or 8.4 media. Motility remained above 50% until 8 h. Washing in pH 7.6, 8.0, or 8.4 media induced more acrosome reactions after incubation than washing at pH 7.2. Percentage of acrosome-reacted sperm increased at each successive time period. Sperm penetrated more oocytes at 4, 6, and 8 h when wash medium pH was fixed at 7.2 and capacitating media pH was raised at .4 unit increments from 7.2 to 8.4. When sperm were washed in pH 7.2 medium, the postincubation penetration rates peaked at 8 h. With wash media of pH 7.6, 8.0, or 8.4, the postincubation penetration rates peaked at 4 h and then gradually declined. In conclusion, the most effective system for capacitating bull sperm was a pH 7.6 wash followed by capacitation in pH 7.6 medium for 4 to 8 h and this system resulted in the highest penetration rates. Wash media pH hastened capacitation but was not a capacitating agent.

Acrosome↗
PubMed1989

Identification of the capacitating agent for bovine sperm in egg yolk-TEST semen extender.

Bovine sperm can be capacitated in egg yolk-TEST buffer. To determine what constituent of the buffer was responsible, ejaculated semen was diluted 1:10 at 37 degrees C with the following 20% egg yolk (vol/vol)-containing buffers: TES-Tris, TES-tetramethylammonium hydroxide, taurine-Tris, citric acid-Tris, citrate, egg yolk salts, egg yolk proteins Tris, and citrate-taurine. Buffers were pH 7.6 and 321 to 325 mOsmol/kg. Extended semen was cooled slowly to 4 degrees C and stored 8 h. Sperm taken at 0 and 8 h were washed in pH 7.6 bovine serum albumin-saline and assessed for motility and capacitation using zona-free hamster eggs. Sperm motilities at 0 and 8 h were similar (60 to 73%) in all extenders except citric acid-Tris (54%) and egg yolk proteins Tris (15%). Bull sperm, stored 8 h in egg yolk-TEST, became capacitated. Because sperm storage in egg yolk-citrate did not result in penetration, both egg yolk and citrate were ruled out as capacitating agents. Capacitating activity resided in the TES and Tris molecules. The TES molecule contains a Tris component and this capacitated bull sperm. The TES molecule also contains a taurine component. However, taurine was not a capacitating agent for bull sperm. In conclusion, both TES- and Tris-containing buffers, alone or together (TEST), were equally effective in capacitating bull sperm.

Animals↗
PubMed1989

Evaluation of calcium-free Tyrode's sperm capacitation medium for use in bovine in vitro fertilization.

Our objective was to determine if a bovine sperm capacitation technique, developed with zona-free hamster oocytes, could be used for the in vitro fertilization of in vitro matured bovine zona-intact oocytes. Bovine cumulus-enclosed primary oocytes from 2- to 5-mm follicles were matured in tissue culture Medium 199 containing Earle's salts and bicarbonate and supplemented with 10% fetal calf serum, FSH (10 micrograms/ml), and estradiol-17 beta (1.5 microgram/ml) for 24 h at 37 degrees C under paraffin oil. Ejaculated bovine sperm, washed thrice in bovine serum albumin-saline (pH 7.6) and capacitated for 4 h in Ca(++)-free Tyrode's medium (pH 7.6), were diluted to 2 x 10(6) sperm/ml in Medium 199 supplemented with 10% fetal calf serum. Oocytes were added (10/500 microliters droplet) to this medium containing the capacitated sperm, freeze-thawed killed sperm, or no sperm and incubated for 8 h before transfer to fresh medium and then incubated for 40 h. At the end of each incubation, a portion of the oocytes were stained and evaluated for development or fertilization. After 24 h of culture, 49% of the oocytes had matured (metaphase II). Fertilization rates were 55.6% after exposure of all oocytes to Ca(++)-free Tyrode's capacitated sperm and 82.5% if only metaphase II oocytes were selected. The parthenogenetic controls were negative (1.4% and 0%). Therefore, the Ca(++)-free Tyrode's sperm capacitation technique can be used for bovine in vitro fertilization studies.

Animals↗