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Biomedical subjects

W S Hunter

Publications and source records attributed to W S Hunter.

At least 37 records · Page 2Linked to original sources
PubMed1988

Prenatal diagnosis of del(11)(p13p15).

Prenatal diagnosis of del(11)(p13p15) was made on cultured amniotic fluid cells and confirmed on fetal skin fibroblasts after termination of pregnancy. Both irides appeared behind schedule in development by 2-3 weeks in reference to the gestational age of the fetus. It is suggested that the aniridia of the aniridia--Wilms tumour association is due to developmental arrest. Confirmation of this complex is difficult at mid-gestation without critical pathological study of the eyes.

Adult↗
PubMed1987

Thermal stimulation of the hypothalamus does not evoke the acute-phase reaction.

Interleukin-1 (IL1) injected into the preoptic-anterior hypothalamus (POAH) induces, besides fever, the hepatic synthesis of acute-phase glycoproteins. Since the febrigenic action of IL1 may involve thermosensitive neurons in the POAH, this study examined whether such neurons also might mediate the acute-phase response (APR). The POAH of six adult NZW rabbits was cooled (Tpo = 34.4 +/- 0.4 degrees C [mean +/- SD]) or heated (40.6 +/- 0.2 degrees C) continuously for 2.5 hr (so as to mimic the mean febrile course following a bolus microinjection of IL1 into the POAH). The ambient temperature (Ta) was 23.5 +/- 1.0 degrees C. Expectedly, core temperature fell and skin temperature rose on POAH heating, and the opposite occurred on POAH cooling. However, no statistically significant changes in the plasma levels of Fe, Zn, Cu, and N-acetylneuraminic acid, as indices of the APR, were induced by these treatments. These results indicate, therefore, that the central actions of IL1 in inducing fever and the APR are separate, and that the APR is not mediated through stimulation of thermosensitive units in the POAH.

Acute-Phase Proteins↗
PubMed1987

The effects of Fränkel II treatment on arch width and arch perimeter.

Changes in dental arch width and total arch perimeter in 24 Class II, Division 1 patients treated with the Fränkel II appliance were compared with changes in an untreated control group. Measurements were made on pretreatment and posttreatment plaster casts at three points on each of four maxillary and four mandibular teeth. Increases in width were computed at the occlusal point and compared for the two samples. A significant increase in occlusal arch width for all measures was suggestive of both a minor tipping movement of the maxillary teeth and a bodily movement of the mandibular teeth. Width development in the maxilla was greater than in the mandible. Occlusal arch width increased more in the molar and premolar regions in the maxilla and in the premolar region in the mandible. Wide arches were found to have as much increase as narrow arches. The total arch perimeter decreased significantly less in the treatment sample than in the control sample. The documented gains in arch width and arch perimeter would not be sufficient to relieve severe crowding, but could be useful in avoiding removal of teeth in borderline extraction cases.

Activator Appliances↗
PubMed1987

The depth of the mandibular antegonial notch as an indicator of mandibular growth potential.

The craniofacial characteristics and growth potential of 25 orthodontically treated patients with deep mandibular antegonial notch were compared with a similar group of 25 shallow notch subjects by the use of longitudinal lateral cephalometric radiographs. Deep notch cases had more retrusive mandibles with a shorter corpus, smaller ramus height, and a greater gonial angle than did shallow notch cases. The lower facial height in the subjects with a deep mandibular notch was found to be longer, and both the mandibular plane angle and facial axis were more vertically directed. During the average 4-year period examined, the deep notch sample experienced less mandibular growth as evidenced by a smaller increase in total mandibular length, corpus length, and less displacement of the chin in a horizontal direction than did the shallow notch sample. The results of this study suggest that the clinical presence of a deep mandibular antegonial notch is indicative of a diminished mandibular growth potential and a vertically directed mandibular growth pattern.

Adolescent↗
PubMed1987

Neodymium-YAG transscleral cyclocoagulation in rabbit eyes.

Transscleral ruby cyclocoagulation has been successfully used to lower intraocular pressure. The recent commercial availability of Nd-YAG lasers with a thermal mode provides a possible alternative by which to perform this procedure. We treated one eye of seven pigmented rabbits using the thermal mode of the Nd-YAG laser. The intraocular pressures were followed up for three months. The treated eyes had significantly lower mean intraocular pressures were followed up for three months. The treated eyes had significantly lower mean intraocular pressures than the untreated contralateral eyes (p less than 0.001). Moreover, the decrease was sustained over the three-month duration of the study. Pathological examination revealed very selective destruction of the ciliary processes, with sparing of the overlying ciliary muscle, sclera, and conjunctiva. The potential value of this mode of therapy for use in patients with glaucoma is discussed.

Animals↗
PubMed1987

Thermoregulatory responses of guinea pigs with anteroventral third ventricle lesions.

Guinea pigs with anteroventral third ventricle region (AV3V) lesions fail to develop fever and the associated rise in acute-phase plasma protein levels following systemic injections of lipopolysaccharide (LPS). Since endogenous pyrogen (EP) injected directly into the preoptic area of animals with AV3V lesions causes appropriate elevations in core temperature (Tco) and acute-phase plasma proteins levels, the blocked responses to LPS probably are not due to damage to the adjacent preoptic area. We proposed, therefore, that EP may pass from blood into brain in the AV3V, presumably through the organum vasculosum laminae terminalis. However, the possibility that a more generalized impairment due to damaged pathways within the AV3V could account for the observed effects was not examined. To investigate this possibility, guinea pigs were given AV3V lesions. Pending histological verification of the ablated sites, AV3V lesions were presumed to be placed correctly if the animals did not develop fever following LPS (Salmonella enteritidis, 2 micrograms/kg i.p., at ambient temperature (Ta) 22 degrees C); those failing to meet this criterion were designated as sham-operated. Two experiments were conducted. In the first, metabolic rates, Tco, and two skin temperatures (Tsk) were measured at Ta 12 degrees, 22 degrees, and 32 degrees C over an 8-month postlesion period during which failure to fever persisted; the data were collected during a 30-min period after thermal balance had been achieved at any given Ta. There were no differences in the variables measured between sham-operated and AV3V-lesioned animals at Ta 22 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Regional surface areas of spontaneously hypertensive and Wistar-Kyoto rats.

Regional skin surface area and region-specific weighting factors for calculating mean skin temperature have not been determined for the rat. Therefore, measurements were made of total skin surface area segmented into five regions of 12 spontaneously hypertensive (SHR) and 12 normotensive Wistar-Kyoto (WKY) rats. SHR's were selected because chronically elevated core temperature and reduced ability of SHR's to withstand heat stress make them of interest for thermoregulatory studies. Area was determined by coating the skin with rubber base dental impression material, then measuring the area of the coating. The relationship between total skin surface area and mass of SHR's was not different from that of WKY's and is described by the equation SA = 8.62 M0.67. However, the ears of SHR's had larger surface area and their tails smaller surface area than those of WKY's. For the combined groups, the proportion of total surface area of the regions was as follows: ears, 0.022; front feet, 0.017; hind feet, 0.040; tail, 0.100; central skin, 0.826. These data provide a basis for calculating skin surface area, mean skin temperature, and related values for SHR and WKY rats.

Animals↗
PubMed1987

Factors producing elevated core temperature in spontaneously hypertensive rats.

Core temperature (Tco) of the spontaneously hypertensive rat (SHR) is consistently higher by approximately 1 degree C than that of normotensive controls. To analyze factors producing the elevated Tco, mean skin temperature (Tsk), metabolic heat production (M), respiratory evaporative heat loss (Eres), effective tissue thermal conductance (K), systolic blood pressure (BP), and Tco were determined in eight male SHR and nine male normotensive Wistar-Kyoto (WKY) rats habituated to rest quietly in neck stock restraint while exposed to ambient temperatures (Ta) of 12.5, 17, 23, 28.5, 32, 34, and 35 degrees C. At all temperatures steady-state BP, Tco, and M were higher for SHR's than for WKY's. SHR's could maintain thermal balance up to Ta 32 degrees C, and WKY's up to 34 degrees C. Eres from SHR's was greater than from WKY's at Ta of 12.5, 17, and 28.5 degrees C. K of SHR's was not different from or was higher than K of WKY's, and K for both groups was 2.6 times greater at Ta 32 degrees C than at 17 degrees C. These results indicate that the high Tco of SHR's is due to increased M uncompensated by increased K or Eres.

Animals↗
PubMed1986

Secular trends in face size.

Comparison of lateral and postero-anterior radiographs of parents and their adult children shows a differential secular trend in facial depths, heights, and breadths. Children tend to have deeper, longer, and narrower faces than their same-sex parents.

Adult↗
PubMed1986

Thermoregulatory and acute-phase responses to endotoxin of full- term-pregnant rabbits.

Fever, a fall in the plasma level of iron (Fe), and rises in the levels of certain plasma glycoproteins (indexed by protein-bound-N-acetylneuraminic acid [NANA]) normally occur during infection; they are thought to be mutually enhancing in host defense. It has been reported that fever is suppressed at full term of pregnancy; however, it is not known whether the blood chemical changes are similarly affected. Also, the mechanism for the suppression of fever is controversial. Since uteroplacental blood flow is at its maximum near term, competition between the demands of the fetoplacental unit and of thermoregulatory effectors might result in underperfusion of thermogenic tissues and therefore provide a basis for the lack of fever. To examine these questions, the changes in colonic temperature (Tco) and regional blood flow induced by Salmonella enteritidis endotoxin (LPS, 2 micrograms/kg iv) were compared in conscious nonpregnant and 30-day-pregnant rabbits 35 min after injection, using 15-microgram radiolabeled microspheres. In different rabbits, the effects of LPS on Tco and plasma Fe and NANA levels were measured before mating and at term. LPS induced fevers similar in heights and courses in both nonpregnant and full-term pregnant rabbits It caused decreases in the blood flows to brain, tongue, mammary gland, small intestine, and ear and increases in the blood flows to masseter muscle, bone, liver (hepatic artery), and left ventricle; blood flows to the kidneys, spleen, right ventricle, ovaries, and myometrium did not change. There were no significant differences in these vascular responses between nonpregnant and 30-day-pregnant rabbits, except a 28% reduction in the blood flow to the placentas.

Animals↗
PubMed1985

Cephalometric changes associated with treatment using the activator, the Fränkel appliance, and the fixed appliance.

Treatment with the activator, the Fränkel appliance, and the edgewise appliance was compared in three separate groups; each group consisted of twenty-five nonextraction cases of Class II, Division 1 malocclusion. Hard- and soft-tissue profile changes caused by growth and treatment were assessed by means of pretreatment and posttreatment lateral cephalograms. Anterior movement of A point was 1.6 mm more in the activator group than in the fixed-appliance group. The most anterior point on the maxillary incisor moved 1.5 mm more distally in the fixed-appliance sample than in the functional groups. Among the three groups, the activator sample showed the most anterior movement of the mandible (2.3 mm); the fixed group showed the least (0.6 mm). The fixed-appliance group showed more posterior rotation of the mandible than the activator group. However, relative to cranial base, the movement of the mandibular symphysis was not statistically different in the three groups. There were little differences among the treatment groups with regard to changes in the soft-tissue profile. In clinical terms, there was a remarkable similarity in the changes that occurred in the three treatment groups.

Activator Appliances↗
PubMed1984

Differential acute-phase responses in febrile and cold- and heat-exposed rabbits.

Endotoxin (LPS) characteristically provokes both fever and the acute-phase reaction (APR). The present studies were undertaken to determine whether these two responses are mutually dependent or controlled separately. Rabbits were injected with LPS (2 micrograms/kg, IV) or exposed to heat (37 +/- 1 degree C) such that the patterns and magnitudes of the body temperature (Tco) rises (1.6 +/- 0.5 degrees C) were similar. While the plasma levels of Fe and Zn decreased, and those of Cu and N-acetylneuraminic acid (NANA) increased significantly after LPS-induced fever, no such changes occurred after heat-induced hyperthermia. In subsequent study, different rabbits were exposed to cold (3 +/- 1 degree C), first furred, then sheared. While furred, they thermoregulated by cutaneous vasoconstriction, whereas, while shaved, they additionally increased their metabolic rates. However, in neither case were the plasma levels of Fe, Zn, Cu, or NANA different in comparison to their pre-cooling values (Ta = 22 +/- 1 degree C). It would seem, therefore, that the acute-phase blood responses to LPS (and ultimately, to endogenous pyrogen [EP]) probably are not mediated merely by the rise in the Tco or by the concomitantly induced vascular and/or thermogenic effectors of fever; but rather, the APR appears to be a regulated, separate response to LPS/EP.

Animals↗
PubMed1984

Activation of acute-phase responses by intrapreoptic injections of endogenous pyrogen in guinea pigs.

The acute-phase reaction (APR) is the concatenation of events that develops in response to infectious or other acute inflammatory stimuli. It includes fever and changes in plasma trace metal and glycoprotein levels. Endogenous pyrogen (EP) is believed to be the mediator of the APR. It acts within the preoptic-anterior hypothalamus (PO) to initiate fever; prostaglandins E (PGE) may modulate this action. To determine whether the nonfebrile responses to EP also are mediated by the PO and through PGE, guinea pigs were injected bilaterally intra-PO (iPO) with homologous EP (1 microliter) or PGE2 (0.1 microgram), and their colonic temperatures (Tco) and plasma iron (Fe), zinc (Zn), copper (Cu), and N-acetylneuraminic acid (NANA) levels were measured. For comparison, EP (2 ml) also was injected intraperitoneally (IP). Heat-denatured EP (delta EP) or pyrogen-free saline (PFS) was the corresponding control. Fevers were induced by IP EP (1.0 +/- 0.1 degrees C [mean +/- SD]), iPO EP (1.1 +/- 0.2 degrees C), and iPO PGE2 (1.4 +/- 0.2 degrees C); neither delta EP nor PFS was pyrogenic. Plasma Fe and Zn levels were decreased significantly after IP EP, but unchanged after iPO EP and PGE2. Plasma Cu and NANA levels were elevated significantly following both IP and iPO EP, but not after iPO PGE2. delta EP or PFS did not cause any changes, by either route. It appears, therefore, that EP-induced fever and rises in plasma Cu and NANA are mediated by the PO, while the decreases of plasma Fe and Zn are direct, peripheral effects. On the other hand, PGE2 appears to be involved only in the central febrile response. Indeed, guinea pigs, pretreated with indomethacin (5 mg/kg, IP), and injected iPO with EP or IP with S. enteritidis endotoxin (2 micrograms/kg), did not develop fever, but exhibited the rise in plasma Cu and NANA.

Animals↗
PubMed1983

Suppression of fever after lesions of the anteroventral third ventricle in guinea pigs.

Endogenous pyrogen (EP), injected systemically or intracerebrally, evokes fever and certain changes in plasma trace metal and glycoprotein levels which are characteristic of the acute-phase reaction. It is generally assumed that EP enters the brain from the blood, although it has not yet been demonstrated that EP crosses the blood-brain barrier (BBB). The possibility that EP might penetrate the brain through the organum vasculosum laminae terminalis (OVLT), which is outside of the BBB and located in close proximity to the medial preoptic region (MPO, the primary site sensitive to locally applied EP), was investigated by making electrolytic lesions (3 mA, 20 sec, anodal) in the anteroventral wall of the third ventricle of guinea pigs (AV3V-X). After 10 days, their febrile and selected acute-phase responses (plasma iron, zinc, copper, and sialic acid levels) to endotoxin (LPS, S. enteritidis, 2 micrograms/kg, IP), which induces EP production by the host, were measured; controls were sham-operated guinea pigs. LPS did not induce in the AV3V-X animals either fever or rises in plasma copper and sialic acid levels; however, as in the controls, it caused hypoferremia and hypozincemia. To exclude damage to the MPO as a cause of these responses, sham and AV3V-X guinea pigs were administered homologous EP intrapreoptically (1 microliter bilaterally). Comparable fevers developed in both groups of animals. Hence, the integrity of the AV3V region including the OVLT seems to be critical for the EP-induced elevations of both body temperature and plasma levels of acute-phase proteins, but not for the fall of plasma iron and zinc levels. It may be that EP passes into the brain through the OVLT.

Animals↗