Biomedical subjects

H C Lin

Publications and source records attributed to H C Lin.

At least 307 records · Page 17Linked to original sources

PubMed1994

A double-blind randomized controlled trial of colchicine in patients with hepatitis B virus-related postnecrotic cirrhosis.

The preliminary results of a prospective double-blind controlled trial of colchicine in 100 patients with hepatitis B virus-related cirrhosis are reported. The patients, 94 males and 6 females, aged 32-80, were assigned to receive either 1 mg of colchicine or an identical placebo orally on a daily basis. The duration of the follow up ranged from 15 to 51 months (median 26 months). Seventy percent had histological proof of cirrhosis. On entry, 80 patients were in Child-Pugh class A, 19 were in class B, and one was in class C. Compared to the placebo group, there was no improvement in the colchicine group after a 24-month follow up in any of the biochemistry data, for example, serum albumin, alkaline phosphatase, alanine and aspartate aminotransferase, bilirubin, and prothrombin time. The difference in the cumulative survival rates at 51 months did not reach statistical significance (p = 0.8) in either group. There was no histological improvement in 30 patients who were willing to undergo repeated liver biopsies. No trend toward improvement of the hepatic pressure gradient was observed in these patients. The serum levels of aminopropeptide of type III procollagen increased significantly in patients in both groups after 24 months of therapy (1.07 +/- 0.06 vs. 1.36 +/- 0.06 U/ml in the colchicine group, 0.93 +/- 0.09 vs. 1.25 +/- 0.07 U/ml in the placebo group; p < 0.05). In addition, neither the clinical deterioration of cirrhosis nor death was prevented in patients receiving colchicine therapy. This report indicates that colchicine has no effect in the treatment of HBV-related postnecrotic cirrhosis.

Adult↗

PubMed1994

Assessing cognitive abilities and dementia in a predominantly illiterate population of older individuals in Kinmen.

A community survey of dementia was conducted on a Chinese islet. A total of 221 men and 234 women in the age range of 50-92 were assessed. The Cognitive Abilities Screening Instrument (CASI), a 100-point cognitive test designed for cross-cultural studies and adapted in Chinese for individuals with little or no formal education, was administered twice by trained field workers with a retest interval of 3 to 4 weeks. In addition, all participants were assessed by physicians who did not know the CASI scores. The physicians' assessment included a complete neurological examination, plus semi-structured tests and interviews covering cognitive abilities, daily activities, depression, cerebrovascular disease, and Parkinson's disease. Dementia was diagnosed by consensus among the physicians according to the DSM-III-R criteria. Among the 455 participants, 16 cases of dementia were identified, including 13 with probable Alzheimer's disease and 1 each with vascular dementia, Parkinson's disease, and alcoholism. The rates of dementia were 0, 3.9 and 11.5% for the age groups of 50-69, 70-79 and 80-92; and 4.4, 2.0 and 0% for the education groups of 0-1, 2-6 and 7-15 years of schooling. No sex difference was found after controlling for education. The Chinese version of the CASI had an intraclass retest reliability of 0.90. Using a cut-off score of < or = 50 for dementia, the sensitivity was 0.88 and the specificity was 0.94. The preliminary study suggests that the CASI can be used in Chinese populations with generally low education levels and that Alzheimer's disease was the most common type of dementia in this population.

Aged↗

PubMed1994

Elevated serum levels of TNF soluble receptors in patients with positive anti-neutrophil cytoplasmic antibodies.

ANCA are found in various systemic vasculitis and are supposed to play a role in the pathogenesis of the disease, in co-operation with other factors such as cytokines. A total of 36 ANCA-positive and 10 ANCA-negative serum samples were analysed for the presence of TNF soluble receptors (TNF-sR), which are shed from the surface of activated cells and may act as TNF inhibitors. Of the ANCA-positive samples, 67% had elevated TNF-sR75 and 72% had elevated TNF-sR55 compared to ANCA-negative specimens (mean [S.E.] 18.7 [17.3] vs 3.6 [1.5] and 10.5 [9.7] vs 1.9 [0.7] ng/ml, P < 0.01). Elevation of TNF-sR in patients with ANCA suggests that cytokines and their inhibitors are involved in the pathogenesis of ANCA-associated autoimmune diseases.

Analysis of Variance↗

PubMed1994

Study on the vascular reactivity and alpha 1-adrenoceptors of portal hypertensive rats.

1. Vascular hyporesponsiveness in portal hypertension has been demonstrated to various vasoconstrictors including noradrenaline (NA). The present study aimed to determine whether the attenuated vascular responsiveness to NA is due to a change in the affinity or the number of alpha 1-adrenoceptors. 2. Partial portal vein ligation (PVL) was performed in Sprague-Dawley rats to produce portal hypertension. Vascular responsiveness to NA was assayed in portal vein, mesenteric artery or tail artery. The affinity and number of alpha 1-adrenoceptors were determined by specific binding of [125I]-HEAT (2-beta-4-hydroxy-3-iodophenyethyl-aminomethyltetralone). 3. In the presence of yohimbine (10(-7) M, an alpha 2-adrenoceptor antagonist), propranolol (10(-6) M, a beta-adrenoceptor antagonist), and two catecholamine uptake inhibitors, desipramine (10(-7) M) and normetanephrine (10(-6) M), the maximum responses to NA were decreased in all three blood vessels of PVL rats: 45% decrease in portal vein, 25% in mesenteric artery and 18% in tail artery. 4. The EC50 values of NA and the pA2 values of prazosin, an alpha 1-adrenoceptor antagonist, in all three blood vessels were not significantly different between sham-operated and PVL rats. 5. The KD and Bmax values for specific binding of [125I]-HEAT or the Ki values for NA in the crude membrane preparations of either mesenteric artery or tail artery were also not significantly different between the two groups. 6. It is concluded that the vascular hyporesponsiveness to NA in the mesenteric artery or tail artery of PVL rats is not due to changes in the affinity or number of alpha 1-adrenoceptors.

Adrenergic alpha-1 Receptor Antagonists↗

PubMed1994

Comparison of tiletamine-zolazepam-ketamine and tiletamine-zolazepam-ketamine-xylazine anaesthesia in sheep.

The anaesthetic effects of intravenous tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg (TK) and tiletamine-zolazepam 6.6 mg/kg-ketamine 6.6 mg/kg-xylazine 0.11 mg/kg (TKX) were evaluated in six wethers. Heart rate, respiration rate, arterial blood pressure, and the electrocardiogram were monitored during anaesthesia. Analgesia was tested by electrical stimulation in the left flank. Atropine (0.03 mg/kg) was given intramuscularly before induction, but after recording of baseline heart rate and respiratory rate. The duration of analgesia was 28.7 +/- 6.9 min with TK and 82.8 +/- 26.6 min with TKX. Heart rate increased significantly within 5 min after TK or TKX administration. Respiratory rate remained unchanged after TK administration, but increased significantly from 5 to 45 min after TKX administration. Arterial blood pressure decreased significantly at 15 min with TK and 30 min with TKX. Sheep remained recumbent for 201 min with TK and 166 min with TKX. All recovered uneventfully. We conclude that either TK or TKX may be used for anaesthetising sheep.

Anesthesia, Intravenous↗

PubMed1994

Studies on the synthesis of some xanthonoid derivatives possessing antiplatelet effects.

2,3- and 3,4-Dihydroxyxanthone react with ethyl 2,3-dibromopropanoate to form the new, substituted 1,4-benzodioxanes 3 and 4, respectively. The regioisomers 3a and 3b; 4a and 4b were separated by column chromatography and characterized for evaluation of the antiplatelet effects in rabbit washed platelets and human platelet-rich plasma. The ethoxycarbonyl derivatives 3a (20 microM) and 3b (20 microM) strongly inhibited the aggregation of rabbit washed platelets induced by arachidonic acid and collagen. The compound 4b showed the most potent inhibition of rabbit washed-platelet aggregation induced by arachidonic acid (IC50 = 8.3 microM). Of the compounds tested in human platelet-rich plasma, compound 4b exhibited the most potent inhibition of primary and secondary aggregation induced by adrenaline (IC50 = 8.6 microM). We conclude that the antiplatelet effects of these four ethoxycarbonyl derivatives are mainly due to an inhibitory effect on thromboxane formation and interference in the adrenaline-receptor interaction.

Animals↗

PubMed1994

Silicone-specific blood lymphocyte response in women with silicone breast implants.

A blinded cross-sectional study was carried out with 99 women, 44 of whom had silicone breast implants. Group I consisted of 55 healthy volunteer women without breast implants; group II comprised 13 volunteer women with breast implants or explants who felt healthy; group III comprised 21 volunteer women with breast implants who had chronic fatigue, musculoskeletal symptoms, and skin disorders; and group IV comprised 10 women who had their prostheses explanted but still presented with clinical symptoms similar to those of the women in group III. Proliferative responses of peripheral blood mononuclear cells from all 99 women were measured by [3H]thymidine uptake after exposure to SiO2 silicon, or silicone gel. The levels of proliferative responses were expressed as stimulation indices, which were obtained by dividing the counts per minute of stimulated cells by the counts per minute of unstimulated cells. Abnormal responses to SiO2, silicon, or silicone gel were defined as a stimulation index of > 2.8, > 2.1, or > 2.4, respectively. Abnormal responses were observed in 0% of group I, 15% of group II, 29% of group III, and 30% of group IV (P < 0.0005 for group I versus groups II and IV). Thirty-one percent of symptomatic women with silicone gel breast implants had elevated serum silicon levels ( > 0.18 mg/liter); however, there was no significant correlation between abnormal cellular responses and silicon levels in blood serum, type of implant, time since first implantation, prosthesis explantation, number of implants, or report of implant leakage or rupture.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Implants↗

PubMed1994

Stimulation of duodenal motility by hyperosmolar mannitol depends on local osmoreceptor control.

Duodenal motility is stimulated by hyperosmolar solution. Since intestinal distension also stimulates intestinal motility, this increase in the motility response may be due to either stimulation of duodenal local osmoreceptor control or intestinal distension resulting from osmotic equilibration. To test which mechanism is primarily responsible for this osmotically sensitive effect, we compared the number of duodenal spike bursts in five dogs equipped with duodenal fistulas that allowed for the preservation or removal of intestinal distension. The response to 300 vs. 1,200 mosM mannitol was compared under three experimental perfusion methods: 1) distension was preserved both proximal and distal to the fistula (DD); 2) distension proximal to the fistula was removed (rD); and 3) distension both proximal and distal to the fistula was removed (rr). The test solutions had access to either the whole gut (DD and rD) or only the first 10 cm of the duodenum (rr). We found that 1) there were more spike bursts after the hyperosmolar solution (dose effect, P < 0.05, analysis of variance); 2) there was no significant difference between the three experimental methods; and 3) the stimulating effect of hyperosmolar solution depended on the first 10 cm of the duodenum. Thus, since hyperosmolar solution increased duodenal motility regardless of whether intestinal distension was preserved or removed, the stimulating effect of hyperosmolar solution on duodenal motility was primarily the result of a local osmoreceptor control mechanism located in the first 10 cm of the duodenum.

Analysis of Variance↗

PubMed1994

Modulatory effects of endogenous adenosine on epinephrine secretion from the adrenal medulla of the rat.

The purpose of this study was to examine (1) whether endogenous adenosine receptors inhibit the release of epinephrine and norepinephrine from adrenal medulla in response to physiological and pharmacological stimuli and (2) whether the renin-angiotensin system modulates this effect of endogenous adenosine. We used a conscious animal model to approximate normal physiological conditions. Male Sprague-Dawley rats were treated with a surface adenosine receptor antagonist, 1,3-dipropyl- 8-(p-sulfophenyl)xanthine (DPSPX) to explore the effect of endogenous adenosine. Plasma epinephrine and norepinephrine levels in response to hydralazine-induced hypotension were measured in these animals. The same protocol was repeated in rats pretreated with either adrenalectomy or captopril. The results showed that DPSPX treatment significantly increased plasma epinephrine and norepinephrine levels at both baseline conditions and after hydralazine-induced hypotension. The results from the adrenalectomized rats showed that the difference in plasma epinephrine level between the control and DPSPX groups originated from the adrenal medulla. Pretreatment with captopril attenuated the rise of plasma epinephrine and norepinephrine levels in DPSPX-treated animals. This result suggests that endogenous adenosine receptors inhibit epinephrine release from the adrenal medulla and suppress plasma norepinephrine levels. When catecholamine release was stimulated by physiological and pharmacological stimuli, this inhibitory function of adenosine receptors was augmented. The renin-angiotensin system is at least partially responsible for the modulatory function of endogenous adenosine on the catecholamine response as demonstrated in this study.

Adenosine↗

PubMed1994

FL-120A-D', new products related to kinamycin from Streptomyces chattanoogensis subsp. taitungensis subsp. nov. I. Taxonomy, fermentation and biological properties.

Six new kinamycin antibiotics, designated as FL-120A-D' (1-6) were isolated from the culture filtrate of Streptomyces sp. strain IY2-13. Based on its cultural, physiological, morphological and chemical characteristics, this strain was identified as a new subspecies of Streptomyces chattanoogensis and named S. chattanoogensis subsp. taitungensis. These kinamycins have demonstrated a potent activity against Gram-positive aerobic and anaerobic bacteria.

Animals↗

PubMed1994

Cardiovascular effects of human parathyroid hormone and parathyroid hormone-related peptide.

Parathyroid hormone (PTH) is hypotensive in mammals and is a potent coronary vasodilator. Parathyroid hormone-related peptide (PTHrp) has been reported to have similar vascular activity. In the present study, the effects of human PTH (hPTH) and human PTHrp (hPTHrp) were compared in various in vivo and in vitro assays. In vivo studies included blood pressure measurement and coronary blood flow determination with labeled microspheres in anesthetized and cannulated normotensive rats. Isolated rat tail artery and portal vein helical strips were used in studying tension development in vitro. In the blood pressure assay, PTHrp was several times more potent than PTH. PTHrp was also significantly more potent than PTH in relaxing tail artery precontracted with arginine vasopressin (AVP). PTHrp and PTH both inhibited the spontaneously contracting portal vein, but again PTHrp was significantly more potent. PTHrp (1 microgram/kg) produced a greater increase in coronary blood flow as compared with the same dose of PTH. These data suggest that PTHrp is more potent than PTH in its cardiovascular actions. It is possible that PTHrp is the endogenous vasodilating ligand, and the structural similarity between PTH and PTHrp may explain the pharmacological action of PTH. It is therefore unlikely that PTH or PTHrp may be involved in the genesis or maintenance of hypertension. Because the parathyroid gland seems to be involved in some forms of essential hypertension, factor(s) other than PTH or PTHrp may be responsible.

Animals↗

PubMed1994

The pressor effect of nicotine in the rostral ventrolateral medulla of rats.

It has generally been assumed that nicotine acts in autonomic ganglia to raise blood pressure. We considered that the pressor effect of nicotine might also involve central mechanisms. We tested this hypothesis in male Sprague-Dawley rats, Wistar-Kyoto (WKY) rats, and spontaneously hypertensive rats (SHR). The animals were anesthetized with urethane and blood pressure was monitored intraarterially. Nicotine was microinjected into various sites in the medulla using stereotaxic technique. While nicotine elicited bradycardia and hypotension in the nucleus tractus solitarii and area postrema, its injection into the rostral ventrolateral medulla (RVLM) produced a does-related and long-lasting increase in both systolic and diastolic pressure. This pressor effect of nicotine was not influenced by muscarinic receptor blockade (atropine 2.9 mumol intravenously), but was completely abolished by local nicotinic receptor blockade (hexamethonium 2.7 nmol). The WKY rats responded to nicotine administration into the RVLM with approximately equivalent changes in systolic and diastolic blood pressure and heart rate. The SHR was more sensitive to nicotine than WKY rats in producing pressor effect when it was injected into the RVLM. Thus, the increase of blood pressure consequent to nicotine is acting through nicotinic receptors in RVLM. These findings suggest a role for medullary nicotinic receptors in neural cardiovascular control and reveal an enhanced sensitivity to this effect of nicotine in the spontaneously hypertensive rat.

Animals↗

PubMed1994

Rearrangement and altered expression of the NFKB-2 gene in human cutaneous T-lymphoma cells.

The NF-kappa b/Rel and I kappa B proteins are important regulators of lymphocyte activation and gene expression. We have identified a rearrangement of the NFKB-2 gene in the HUT 78 human cutaneous T-cell leukemia (CTCL) line, cDNA and genomic DNA sequence predicted the presence of a truncated 80 kD NFKB-2 precursor protein (p80HT), instead of the normal p100 protein. No wild-type allele was identified. Elevated levels of two aberrantly sized RNAs were detected, and high levels of p80HT and processed p52 protein were present in HUT 78 cell nuclei. The p52 protein bound to a palindromic kappa B DNA motif, however p80HT did not. Rearrangement of the NFKB-2 gene was also detected in DNA from two patients with CTCL. Rearrangement and overexpression of the NFKB-2 gene may contribute to the genesis of a subset of T-cell malignancies.

Amino Acid Sequence↗

PubMed1994

Stress fractures of the ribs in amateur golf players.

BACKGROUND: Stress fractures of the ribs are sometimes seen at the Outpatient Department in patients with a history of playing golf enthusiastically. Many are diagnosed as "muscle strain" or "myofascial pain" and patients are simply advised to take some rest or are treated with analgesics and local injection. This case study investigated 11 amateur golfers whose chief complaint was anterior, posterior or lateral chest pain. After X-ray and bone scan evaluation, "stress fracture of the ribs" was diagnosed. A questionnaire presented to them trying to find the possible mechanisms of these stress fractures. Biomechanical analysis showed that the bending force of the ribs was located at posterolateral segments where fractures tend to occur. Overuse, poor technique and inadequate stretch in beginners are postulated as causes for apparent increased susceptibility to these skeletal injuries. METHODS: Questionnaires inquired about (1) warm-up time, (2) number of strikes, (3) fracture sites, (4) pain patterns, (5) combined injuries. RESULTS: All 11 patients were beginners with right side hand dominance who had begun to play golf within the year. Right side ribs fracture occurred in six cases; left side ribs fracture occurred in eight cases including three patients with two fracture sites. Localized pain was reported in six cases and there were five cases with radiating pain along costal margins. All the golfers had spent no more than 10 minutes in warm up them. Seven patients suffered from multiple injuries after they had played. Five were diagnosed by X-ray and six showed positive finding after Tc-99m MDP bone scan. All lesions were located at the posterolateral segments of the ribs. CONCLUSIONS: Stress fractures of the ribs in amateur golfers are certainly not uncommon. Predominant muscle forces are generated by forced coupling of scapular retraction and protraction, acting through the serratus anterior. With early diagnosis and relative rest for four to eight weeks, the pain will improve. Overuse, poor technique and inadequate stretch will probably lead to stress fracture of the rib.

Biomechanical Phenomena↗

PubMed1994

Clinical and clinicopathologic changes in cows with endotoxin-induced mastitis treated with small volumes of isotonic or hypertonic sodium chloride administered intravenously.

We characterized the clinicopathologic manifestations of experimentally induced endotoxin-induced mastitis. Responses to hypertonic fluid therapy also were assessed. Eight cows received 1 mg of endotoxin by intramammary infusion in the left forequarter. Four hours after endotoxin administration, cows received 0.9% NaCl, 5 ml/kg of body weight (n = 4) or 7.5% NaCl, 5 ml/kg (n = 4) IV. Endotoxin-infused cows had expanded plasma volume, hyponatremia, transient hyperchloremia and hypophosphatemia, increased serum glucose concentration, and decreased serum activities of liver- and muscle-specific enzymes. Calculated plasma volume increased at 6 hours in cows receiving hypertonic NaCl, and at 12, 24, and 48 hours after endotoxin infusion in both groups. Concurrent observations of decreased serum protein concentration, erythrocyte count, and hematocrit supported observations of increased plasma volume. Relative plasma volume was greater in cows receiving hypertonic NaCl (124.3%) than in cows receiving isotonic NaCl (106.6%) at 6 hours after endotoxin infusion. Cattle receiving hypertonic NaCl had increased voluntary water intake after IV fluid administration. Increased water consumption was not accompanied by increased body weight, indicating probable occurrence of offsetting body water loss. Serum sodium concentration in cows receiving hypertonic NaCl was increased 2 hours after fluid administration, but the magnitude of the change was minimal (< 4 mmol/L) and transient, indicating rapid equilibration with either interstitial or intracellular spaces. Serum sodium concentration was decreased in cows receiving isotonic NaCl at 12, 24, and 48 hours after endotoxin administration, compared with concentration prior to endotoxin administration, indicating selective loss of sodium.

Analysis of Variance↗

PubMed1994

A case report on the use of guaifenesin-ketamine-xylazine anesthesia for equine dystocia.

In 4 mares suffering from dystocia, general anesthesia was induced with xylazine (1.1 mg/kg, IV) and ketamine (2.2 mg/kg, IV) and maintained with continuous intravenous infusion of ketamine (2 mg/ml), xylazine (0.5 mg/ml) and guaifenesin (50 mg/ml) in 1 L of 5% dextrose. The duration of the procedure of these mares were 40, 45, 180, and 35 minutes, respectively. For procedures required more than 1 hour (Mare 3), the dose of ketamine and xylazine in the mixture was reduced to 1 mg/ml and 0.25 mg/ml, respectively. Average infusion rate of the mixture used to maintain anesthesia for each mare was 2.5, 2.67, 2.28, and 2.21 ml/kg/hr. Recovery to standing occurred at 55, 75, and 180 minutes after termination of infusion for mares 1, 2, and 3, respectively. Xylazine reversal agent, tolazoline (2.2 mg/kg), was given to mare 1 to hasten the recovery; the mare stood within 30 minutes after tolazoline administration. Continuous infusion of guaifenesin-ketamine-xylazine can be an alternative anesthetic technique for prolonged obstetrical procedures under field conditions when suitable anesthetic equipment is not available. If recovery to standing is extended over 30 to 40 minutes, yohimbine or tolazoline can be administered to hasten recovery.

Anesthesia, General↗

PubMed1993

Immunohistochemical study of catecholamine enzymes and neuropeptide Y (NPY) in the rostral ventrolateral medulla and bulbospinal projection.

The purpose of this study was to determine whether neuropeptide Y (NPY) terminals in the intermediolateral spinal cord originate from the rostral ventrolateral medulla (RVLM). Immunohistochemical staining of tyrosine hydroxylase (TH), dopamine-beta-hydroxylase (DBH), phenylethanolamine-N-methyltransferase (PNMT), and NPY in the rat brainstem and spinal cord were performed in this study in order to examine consequences of lesions of the RVLM and of intracisternal injections of 6-hydroxydopamine (6-OHDA) on catecholamine and NPY immunoreactivity in the intermediolateral column (IML) of rats. In addition, ricin, a retrograde neurotoxin, was applied in the superior cervical ganglion (SCG) to determine its effect on catecholamine and NPY immunoreactivity in the IML. Computer-aided image analysis was used to quantify the immunohistochemical changes in the RVLM and spinal cord. The results demonstrated that many catecholamine- and NPY-containing neurons and/or fibers existed in the RVLM and their terminals were found in the IML. After administration of 6-OHDA intracisternally, the catecholamine and NPY immunoreactivities were decreased both in the brainstem and IML of the spinal cord. Following unilateral microinjection of 6-OHDA into the RVLM, the number of NPY- and catecholamine-containing neurons decreased and there was a reduction in neuron terminals on the ipsilateral side. After injection of ricin into the SCG, the catecholamine and NPY neurons of the medulla were not affected, whereas their terminals in the IML decreased ipsilaterally. These results indicate that most of the catecholamine- and NPY-immunoreactive terminals found in the IML originated in the RVLM. These terminals appear to project towards the superior cervical ganglia.

Animals↗

PubMed1993

Human Ig production and isotype switching in severe combined immunodeficient-human mice.

Severe combined immunodeficient (SCID) mice were transplanted with different human fetal organs (SCID-hu mice), including thymus, liver, spleen, and omentum, and the serum levels of human IgM, IgG, IgE, and IgA were measured. In all SCID-hu mice significant levels (up to 590 ng/ml) of IgM were detected, irrespective of the organs transplanted. In contrast, IgG was present (up to 530 ng/ml) only when the fetal thymus was transplanted together with the fetal liver, indicating that the presence of human T cell is a prerequisite for in vivo isotypes switching by human B cells in SCID-hu mice. Additional transplantation of fetal spleen did not significantly increase IgG levels. was observed 4 months after transplantation. At that time, analysis by IEF showed that human IgG present in SCID-hu serum was at least oligoclonal. Furthermore, all IgG subclasses were represented in the human IgG pool. Human B cells were undetectable in the peripheral blood, spleen, and bone marrow of these SCID-hu mice; in contrast, B cells expressing CD19 could be isolated from the SCID-hu thymus. Considerable proportions of the CD19+ B cells coexpressed CD5, CD7, CD10, CD40, and CD2. These B cells spontaneously produced IgM and IgG in vitro and could be induced to switch to IgE-producing cells when cocultured with cloned activated CD4+ T cells in the presence of IL-4. Collectively, these data demonstrate that functionally mature B cells able to produce IgM and IgG in vivo, and IgE in vitro, are present in the SCID-hu human thymus.

Animals↗