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Biomedical subjects

R E Jones

Publications and source records attributed to R E Jones.

At least 163 records · Page 9Linked to original sources
PubMed1984

Compensatory follicular hypertrophy during the ovarian cycle of the house gecko, Hemidactylus frenatus.

The house gecko ( Hemidactylus frenatus ) exhibits an ovarian cycle that can be divided into early follicular, vitellogenic, and luteal phases. Serial sections through the right ovary of animals in the three phases allowed us to quantify follicular size, condition, and number, as well as germinal bed activity. There are six to eight healthy, growing follicles in each ovary, arranged in a stepwise size hierarchy. This number does not vary among the three phases, even though one follicle becomes atretic and one ovulates during each cycle. Therefore, compensatory follicular hypertrophy occurs, leading to replacement of lost follicles and maintenance of the follicular size hierarchy.

Animals↗
PubMed1984

Cascade impactor method for the droplet size characterization of a metered-dose nasal spray.

A relatively rapid and simple method was developed to characterize the droplet size of a metered-dose nasal spray. The study primarily concerned the measurement of the relative proportion of small to large droplets. A small droplet could potentially reach bronchi or alveoli, depending on its size, and was therefore undesirable for the topical corticosteroid therapy of rhinal disease. The nasal spray was a solution of flunisolide, a topically active anti-inflammatory corticosteroid, administered by a manually operated, metered-dose pump spray system. The method utilized a cascade impactor fitted with a glass chamber; the cascade impactor collected and sized droplets into six fractions 0.5-16 micron in diameter, while the glass chamber collected droplets greater than 16 micron in diameter as another fraction. Results showed that the majority of the spray droplets deposited in the glass chamber. Less than 0.5% by weight of the spray dose was delivered in droplets less than 8 micron aerodynamic diameter. These results are in good agreement with the droplet size distribution obtained by laser holography. The cascade impactor method showed that the number of undesirable small droplets produced by the flunisolide nasal spray unit was negligible. The method can be used with other aerosols where there is a similar concern for the inhalation of small particles.

Administration, Intranasal↗
PubMed1984

Nasal absorption of nafarelin acetate, the decapeptide [D-Nal(2)6)]LHRH, in rhesus monkeys. I.

Nafarelin acetate, [D-Nal(2)6]LHRH, a highly potent superagonist of luteinizing hormone-releasing hormone, was given intranasally to six female rhesus monkeys. Absorption was rapid and very reproducible, with peak levels occurring at 15-30 min and a bioavailability of approximately 2% relative to a subcutaneous dose. The nasal dose response was highly nonlinear. The nonlinearity was apparently associated with the absorption phase, since elimination profiles at all doses were similar.

Absorption↗
PubMed1984

Evidence against gamma-crystallin DNA or RNA sequences in the chicken.

A cloned cDNA (pM gamma 1 Crl) encoding about two-thirds of a gamma-crystallin polypeptide from the murine lens was used as a hybridization probe to search for the presence of gamma-crystallin-like RNA or DNA sequences in the chicken. The 15-day-old chicken lens did not contain any RNA sequences homologous to the murine gamma-crystallin cDNA, as judged by Northern blot hybridization. An approximate 2.3 Kbp (kilobase pair) Bam HI fragment from the chicken genome hybridized to the murine gamma-crystallin cDNA in Southern blots. Cloning and sequencing of this genomic fragment, however, did not reveal any homology with gamma- or beta-crystallin sequences. A stretch of 22 dG: dC nucleotides was present in the cloned DNA fragment and possibly this hybridized to the cloned gamma-crystallin cDNA via its dG:dC nucleotide tails introduced during the cloning procedure. These data support those of McDevitt and Croft (1977) indicating that the chicken lens lacks gamma-crystallin and provide evidence against gamma-crystallin mRNA or a gamma-crystallin gene or pseudogene in the chicken. The absence of gamma-crystallin mRNA in the embryonic chicken lens cells makes them potentially useful recipients for investigating the expression of cloned gamma-crystallin genes.

Amino Acid Sequence↗
PubMed1984

Spontaneous, rhythmic contractions of the ovarian follicular wall of a lizard (Anolis carolinensis).

Collapsed walls of vitellogenic follicles from the lizard Anolis carolinensis were placed in an in vitro system to measure contractility. Three initial tensions were utilized, 0.15, 1.5, and 10.0 g; the latter, after relaxation, produced follicles with a tension similar to that on the wall of an intact vitellogenic follicle. Follicles at each tension then were exposed to either saline or 50 ng/ml arginine vasotocin (AVT). Spontaneous, rhythmic follicular contractions occurred (approx one every 3 min), regardless of initial tension. The higher the initial tension, however, the greater the amplitude of the contractions. Treatment with AVT did not influence any parameter of rhythmic contraction. This report of rhythmic contractions of whole follicular walls of Anolis suggests that contractile activity of myofibroblasts in the wall plays a role in follicular growth and/or ovulation.

Animals↗
PubMed1984

Decreased defibrillator-induced dysfunction with biphasic rectangular waveforms.

High-intensity electric shocks used for cardiac defibrillation produce arrhythmias, S-T segment changes, and a low percent success in situ. Cultured myocardial cells exhibit similar postshock arrhythmias that are caused by a prolonged depolarization of the cell membrane. Since this dysfunction is ameliorated by biphasic RLC-type waveforms, we examined rectangular biphasic waveforms to maximize this beneficial effect and clarify the dysfunction-inducing mechanism. Cultured myocardial cells were subjected to electric field stimulation with monophasic 5-ms rectangular waveforms of about 80 V/cm to produce a postshock arrest of contractile activity lasting 4 s. Shocks given with this control waveform were alternated with biphasic test waveforms having the same initial portion followed by negative "tails" 1-100 ms in duration and 5-100% of the initial positive portion in amplitude. Results from 31 biphasic waveforms demonstrated significant alterations in postshock dysfunction. Waveforms with up to 10% undershoot and ranging from 5 to 100 ms in duration decreased arrest time by up to 50%; waveforms with greater than 20% undershoot led to protracted postshock arrest times. These results strengthen the hypothesis that electromechanical breakdown of the myocardial cell membrane underlies postshock dysfunction and show that biphasic waveforms with low amplitude tails ameliorate this dysfunction.

Animals↗
PubMed1984

Combined Coventry-Maquet procedure for two-compartment degenerative arthritis.

The combined Coventry-Maquet procedure has been proposed as a means of treating dual-compartment degenerative arthritis of the knee. The procedure was investigated in a prospective study of 14 patients treated by combined high tibial osteotomy and tibial tubercle elevation. Preoperative scores averaged 50 points and scores at follow-up evaluation averaged 57 points with a modified 100-point total knee grading system. There were no excellent results, one good result, and 13 poor results. Five patients whose results were poor have since had total knee arthroplasty. The combined Coventry-Maquet procedure required too much dissection, had too high a complication rate, and yielded a minimal improvement in knee function and pain. Two-compartment degenerative arthritis should be treated by an alternative method, such as total knee arthroplasty, when surgical intervention is indicated.

Adult↗
PubMed1983

Ovarian, oviductal, and adrenal vascular connections in female lizards (genus Anolis).

The urogenital blood vessels of Anolis equestris and A. carolinensis were studied using dissection, injection of silicone rubber, and histology. A new blood-vascular connection between small veins in the pampiniform plexus at the base of the ovary and an ostial extension of the secondary oviductal vein is described. Chemical messengers could thus be carried in the blood from the ovarian venous drainage to the oviduct. Furthermore, close apposition of the secondary oviductal vein and artery provides an anatomical basis for countercurrent exchange of these messengers. A circular venous arcade, involving the supracardinal vein and branches of the oviductal veins, also is described; this arcade could serve to deliver adrenal hormones to each oviduct.

Adrenal Cortex Hormones↗
PubMed1983

The relationship among ovarian condition, steroid hormones, and estrous behavior in Anolis carolinensis.

The lizard Anolis carolinensis ovulates a single egg alternately from each ovary every 14 days. The ovulated egg enters the ipsilateral oviduct, acquires a shell, and is oviposited 18 or 19 days later. Thus, there is only a single egg in one of the oviducts (one-egg condition) during most of the estrous cycle, but there is a 4-5 day period when a mature, shelled egg is in one oviduct while a recently ovulated egg is in the contralateral oviduct (two-egg condition). Analysis of ovarian follicular diameters indicates that the largest follicle in a single ovary exhibits a growth spurt about halfway through its 28-day vitellogenic growth phase. The corpus luteum, once formed from the ovulated follicle, exhibits a linear decrease in weight, becoming fully regressed just before oviposition of the egg in the ipsilateral oviduct. Plasma concentrations of estradiol-17 beta and progesterone are high in two-egg animals. After oviposition, plasma concentrations of progesterone are still high in one-egg animals whereas those of estradiol-17 beta are much lower. These ovarian and hormonal changes during the estrous cycle are discussed in relation to the probable sources of estradiol-17 beta and progesterone, the control of the alternating pattern of ovulation and oviposition, and the role of steroid hormones in female sexual receptivity in this species.

Animals↗
PubMed1983

Adrenergic inhibition of uterine contractions and oviposition in the lizard Anolis carolinensis.

Injection of arginine vasotocin (AVT), which induces oviposition in several lizard species, fails to do so in Anolis carolinensis. We tested the hypothesis that epinephrine-induced activation of beta-adrenoreceptors in the uterus inhibits AVT action on uterine smooth muscle. Pretreatment of gravid females with the beta-adrenoreceptor antagonist dichloroisoproterenol 15 min before an AVT injection resulted in uterine sensitivity to AVT and subsequent oviposition. Furthermore, in vitro tests indicated that epinephrine as well as a beta-adrenoreceptor agonist (isoproterenol) inhibit uterine tonic and rhythmic contractions that normally follow exposure to AVT. These results suggest that stress-induced secretion of epinephrine can act as a short-term inhibitor of oviposition in this species.

Animals↗
PubMed1983

Histological and immunohistological identification of collagens in basement membranes of Schwann cells of neurofibromas.

The application of immunohistological techniques that use antibodies highly specific for collagen allows new comparative studies in the distribution and deposition of genetically distinct types of collagens in neurofibromas. The identification of collagen type IV in basement membranes is unique and marks particularly the sheaths or cytoplasma of proliferating Schwann cells. Cells with greater degrees of atypia show increased amounts of intracellular collagen in basement membranes by immunohistologic examination, which provides an additional diagnostic tool in dermatopathology.

Basement Membrane↗
PubMed1983

Improved defibrillator waveform safety factor with biphasic waveforms.

Excitation thresholds and arrhythmias were studied in "adult-type" cultured chick embryo myocardial cells after electric field stimulation with biphasic, truncated, and rectified underdamped RLC (resistance-inductance-capacitance) type waveforms, to test the hypothesis that the negative phase of biphasic waveforms ameliorates membrane dysfunction induced by the initial positive portion. Photocell mechanograms and intracellular microelectrodes monitored extrasystoles and depolarization-induced arrhythmias. Rectifying or truncating biphasic waveforms did not alter the excitation threshold. However, shock intensities producing specific postshock arrhythmias or a specific severity of postshock prolonged depolarization differed significantly when biphasic waveforms were truncated or rectified. The voltage gradient producing a specific dysfunction was 12-14% lower for the truncated version than for the biphasic; that for the rectified version was 17-27% lower than for the biphasic version (although both contained the same energy). Safety factor, the ratio between shock intensity producing specific dysfunction and that producing excitation, was determined for each waveform. Biphasic waveforms had larger safety factors than truncated or rectified waveforms. Since safety factor, as measured in cultured myocardial cells, closely corresponds with in situ defibrillating effectiveness (14), the significantly higher safety factors of biphasic waveforms suggest that carefully shaped biphasic waveforms might improve the efficacy and safety of cardiac defibrillation procedures.

Animals↗
PubMed1983

Street people and psychiatry: an introduction.

Homelessness is not a new problem in the United States, but during the current recession we have witnessed an unprecedented increase in the number of people, many of them mentally ill, who live on the streets of American cities. The author traces the history of the homeless mentally ill in the United States; he then discusses the role of media coverage and reports in the scientific literature in alerting the public and the mental health field to the plight of the street people. The impact of deinstitutionalization and the work of advocacy organizations such as the National Coalition for the Homeless and the Philadelphia Committee for the Homeless are also discussed.

Adult↗