[Testing of synthetic vowels in patients with 22 channel cochlear implant]

In the 22 multi-channel cochlear implant system, F0 information determines the frequency of electrical stimulation, and F1 and F2 information determine the number of stimulating electrodes. We performed tests using synthetic vowels on 16 patients who had undergone 22 channel cochlear implant surgery and 6 months' speech rehabilitation. Information transmission rates were calculated to analyze the response pattern. As a result, 1) the vowel recognition ability of patients with cochlear implant surgery correlated with the number of electrodes being used. 2) The value of vowel confusion decreased so as to be separated by a pair of stimulating electrodes, and the confusion in F1 information was regarded to be less than that for F2 information.

Palmar dermatoglyphics in congenital hand anomalies

A palmar dermatoglyphic study of 392 hands of patients with congenital hand anomalies was performed to evaluate the number of digital triradii, the position of an axial triradius, the incidence of hypothenar patterns, the pattern intensity, and the main line index. Remarkable variations, which are rare in normal hands, were frequently observed. The results deviated from the normal range in cases of ectrodactyly and syndactyly, but were within the normal range in cases of polydactyly. The dermatoglyphics associated with each type of hand anomaly was characteristic and discriminative. Dermatoglyphics was also helpful in evaluating the function of the hand, and in estimating the time of the damage to the hand in embryogenesis.

cDNA cloning and expression of a novel human desmocollin

We have cloned a human cDNA encoding for a novel transmembrane protein from a bladder carcinoma cell line (HT-1376) cDNA library. Sequence analysis of this clone revealed an open reading frame of 2,691 bases encoding a protein of 896 amino acids. Sequence comparison showed that this clone has significantly homology to desmocollins, intracellular adhesion molecules belonging to the cadherin superfamily. This protein consists of a signal peptide of 30 amino acids, a precursor segment of 105 amino acids, and a mature protein of 761 amino acids. We expressed this cDNA clone in COS1 cells and found that the predicted cell adhesion molecule remained in the membrane fraction. Antibodies recognizing the predicted mature adhesion molecule of the protein stained antigens along the cell boundaries of both HT-1376 cells and normal human keratinocytes resembling the pattern of desmosome localization. These findings suggest that our clone might be a new member of the desmocollin family, and we have tentatively called this clone human desmocollin type 4.

Purification and biological properties of a cell growth-stimulating factor from Clostridium perfringens FERM P-14028

The active component that stimulates fibroblast growth was purified from cultured Clostridium perfringens FERM P-14028, and a quantitative assay method for the biological activity was established. The active component was named cell growth-stimulating factor (CGSF), and the molecular weight of this factor was estimated to be 420 kDa on gel permeation chromatography. CGSF(50-100 ng/ml) stimulated the growth rate of BHK-21 (C-13) cells in the logarithmic growth phase, and shortened the doubling time by 16-18%, but had no effect on confluent cells. These actions were indicated only with medium containing fetal bovine serum. These results suggest that CGSF is a novel protein that regulates cell growth via a mechanism of action different from that of other growth factors.

[Effect of E. coli endotoxin and D-galactosamine on pathophysiology in rat lungs]

The effects of repeated intravenous injection of E. coli endotoxin (ETX) and intraperitoneal injection of D-galactosamine (GAL), which decreases the circulating level of alpha 1-antitrypsin, on the pathophysiology of chronic lung injury was studied in rats. Four groups were prepared as follows for 8 weeks. Group 1 (control): Intravenous injection of saline. Group 2: Intravenous injection of ETX (2 mg/kg) once a week. Group 3: Intraperitoneal injection of GAL (200 mg/kg), 2 times daily on 3 consecutive days each week. Group 4: Injection of both ETX and GAL, at the same dosages as used in groups 2 and 3. Total lung capacity and static lung compliance divided by weight were high in the ETX group and the ETX + GAL group, comparative when compared with those in the control and GAL groups, even though weight gain rates in the ETX + GAL group was less than in other groups. Mean linear intercept of rats in the ETX + GAL group was significantly greater than in other groups. These results suggest that ETX + GAL-treated rats have more emphysematous changes in pulmonary function and structure.

Immunohistochemical demonstration of p53 protein in colorectal adenomas and adenocarcinomas. Reliable application of the heat-induced antigen retrieval method to formalin-fixed, paraffin-embedded material

Ninety-nine polypoid neoplasms and eight advanced adenocarcinomas of the colon were studied immunohistochemically for p53 protein expression. For reproducible antigen retrieval, formalin-fixed, paraffin-embedded archival sections were heated at 90 degrees C for 120 min in 0.01 mol/L phosphate-buffered saline, pH 7.2, prior to immunostaining. Proliferating cell nuclear antigen served as a positive control marker for effective antigen retrieval. The 99 polyps were categorized into 24 high-grade adenomas, 60 non-invasive cancer-in-adenomas (CIA), and 15 CIA with stromal invasion. All the polyps contained portions of low-grade adenoma. Positive nuclear staining of p53 protein was observed in none of the non-neoplastic mucosa, nine (9%) of 99 low-grade adenomas, 17 (71%) of 24 high-grade adenomas, 46 (77%) of 60 non-invasive CIA, 10 (67%) of 15 invasive CIA, and five (63%) of eight advanced carcinomas. When the antigen retrieval treatment was omitted, the positivity rates were 0, 2, 17, 35, 40, and 63%, respectively. When the antigen-retrieved staining pattern was classified into (i) 'sparse' (< 25% of the nuclei of neoplastic glands labeled), 'scattered' (25-75%) and 'dense' (> 75%); or (ii) 'focal' (the positively labeled glands occupying < 25% of the tumor area), 'intermediate' (25-75%) and 'diffuse' (> 75%), the sparse and focal patterns predominated in high-grade adenomas and non-invasive CIA with low-grade atypia, while the dense and diffuse patterns predominated in invasive CIA and all the advanced carcinomas revealed the dense and diffuse patterns. Non-invasive CIA with high-grade atypia belonged to an intermediate type between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Ultrastructural distribution of growth hormone and prolactin mRNAs in normal rat pituitary cells: a comparison between preembedding and postembedding methods

In situ hybridization (ISH) at the electron microscopic level is essential for elucidating the intracellular distribution and role of mRNA in protein synthesis. We describe our electron microscopic ISH method using biotinylated oligonucleotide probes for rat growth hormone and prolactin mRNAs and compare the preembedding method with the postembedding method. Preembedding electron microscopic ISH localized rat growth hormone and prolactin mRNAs on the polysomes of the rough endoplasmic reticulum (RER). Rat growth hormone mRNA was distributed diffusely on the RER, whereas rat prolactin mRNA was scattered and distributed focally. Thus there might be a specific translational site for prolactin mRNA on the RER. Rat growth hormone mRNA signals were also recognized on the polysomes of the RER, using the postembedding method with streptavidin gold conjugate. The hybridization signal intensity using the postembedding method was lower, and non-specific signals were more frequent, in comparison with the preembedding method. The preembedding method thus appears to be easier and better than the postembedding method from the viewpoint of utility and preservation of mRNA. Electron microscopic ISH is considered to be an important tool for evaluating the intracellular localization of mRNA and the site of specific hormone synthesis on the RER.

IL-5 mRNA expression in blood lymphocytes from patients with Kimura's disease and parasite infection

Blood lymphocytes from patients with eosinophilia are known to produce interleukin-5 (IL-5) with appropriate stimulation in vitro. To determine whether blood lymphocytes from these patients produce IL-5 in vivo, we tested the IL-5 mRNA expression in blood lymphocytes immediately after separation by reverse-transcriptase polymerase chain reaction (RT-PCR) method. We found that lymphocytes from eosinophilic patients expressed IL-5 mRNA, but lymphocytes from normal volunteers did not express the lymphokine. These findings suggest that in patients with eosinophilia, peripheral blood lymphocytes produce IL-5 in vivo.

Long-term results of surgical treatment in infants with total colonic aganglionosis

The authors describe the long-term results of the surgical treatment of total colonic aganglionosis (TCA) in nine boys who have been treated since 1975. The principal operative procedure was endorectal pull-through of the ganglionic ileum, with the aganglionic colon as an onlay patch. The procedure was employed in five infants, using the right or left colon. Ileorectostomy with an onlay patch was used in two patients; ileoanostomy without the patch was used in two. The distal end of the pulled-through ileum was, on average, 39 cm from the ileocecal junction. The average follow-up period was 11.0 years. Diarrhea and distension were temporary after the pull-through, and all patients ultimately tolerated normal feeding. Considering the variation in operative techniques, we were unable to demonstrate any advantage of one procedure over another. Z scores for height and weight at the last follow-up examination correlated with the weight gain before the definitive surgery and inversely correlated with the length of resected distal ileum at the time of operation.

Interleukin-4 inhibits spontaneous and parathyroid hormone-related protein-stimulated osteoclast formation in mice

We examined the in vivo effects of recombinant murine IL-4 (rmIL-4) on spontaneous and stimulated mouse osteoclast formation. EC-GI cells, which produce PThrP and IL-1 alpha, were explanted in nude mice. These EC-GI cell-bearing nude mice developed hypercalcemia (4.90 +/- 0.68 mM), and the calcium levels were decreased to near normal (3.48 +/- 0.73 mM, p < 0.05) at day 3 by continuous infusion of rmIL-4 at a dose of 7 micrograms/day. When infused with 0.6 nmol/day of PTHrP(1-34) in ICR mice, rmIL-4 at a dose of 1 or 5 micrograms/day for 3 days caused a marked inhibitory effect on hypercalcemia induced by PTHrP(1-34) (3.73 +/- 0.56-2.54 +/- 0.14 mM, p < 0.01). However, rmIL-4 alone did not change the serum calcium in mice. Histomorphometric analysis revealed that rmIL-4 inhibits both spontaneous and PTHrP(1-34)-stimulated osteoclast formation in mice, with a decrease in osteoclastic surface and in the number of osteoclasts per mm bone surface, respectively. We conclude that IL-4 inhibits spontaneous and stimulated bone resorption resulting from inhibition of osteoclast formation and modulates the development of humoral hypercalcemia of malignancy.

Atypical simple bone cyst of the mandible. A case report

An atypical case of simple bone cyst involving the ramus and condyle of the mandible in a 7-year-old boy is presented. The literature is briefly reviewed.

[Analysis of DNA contents in hematological malignant cells using whole blood lysis method]

The experiments have been undertaken whether DNA contents could be measured using whole blood lysis method by FACScan. Cell population in the phases of G1, S and G2 + M were well analyzed, when we used 3 x 10(6) cells lysed with 0.1% Triton X-100 in 1 ml of phosphate buffered saline, staining with 30 micrograms/ml of propidium iodide (PI) within 30 min after staining with PI. We have further developed cell cycle analysis for cells bearing lineage specific antigens recognized with FITC-conjugated monoclonal antibodies using two color analysis. When we fixed cells with 50% ice-cold ethanol after staining cells with FITC-conjugated antibodies, positive population ratio in these cells have been unchanged before and after fixing for CD3, CD4, CD5, CD8. CD10, CD19, CD14, CD33, and HLA-DR, but CD7 positive cells were markedly decreased after fixing. Using this method, CD41 positive leukemia cells have 3.4% in S phase and 6.8% in G2 + M phase, while CD41 negative cells have 1.8% in S phase and 2.0% in G2 + M phase in a patient with AML: M7, resulting leukemia cells were rich in S phase and G2 + M phase. The similar results were obtained in patients with AML:M2 using CD33 antibodies. During the clinical course, the changes of the blast numbers were well-correlated with changes of S-phase proportion in the patient with AML:M2. Among 47 patients with hematological malignancies in our hospital tested here, only 2 cases with 4.3% of total patients showed to have aneuploidy in malignant cells. One is a patient with non-Hodgkin lymphoma, the other is myelodysplastic syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of plasma fibrinogen concentration on the inhibition of platelet aggregation after ticlopidine compared with aspirin

BACKGROUND AND PURPOSE

Elevated levels of plasma fibrinogen are a risk factor for cerebral infarction. Because fibrinogen plays a central role in platelet aggregation and binding of fibrinogen to platelets is inhibited by ticlopidine, we studied the effect of the plasma fibrinogen concentration on the antiaggregatory action of ticlopidine compared with that of aspirin.

METHODS

We determined platelet aggregability before and after administration of ticlopidine (200 mg/d) or aspirin (81 mg/d) in 61 stroke patients and correlated the changes with the plasma fibrinogen concentration.

RESULTS

In patients receiving ticlopidine, the platelet aggregability induced by 1, 5, and 10 mumol/L adenosine diphosphate significantly decreased compared with aggregability before medication (P < .05), and the reductions had significant negative correlations with the plasma fibrinogen concentration (P < .05). In patients receiving aspirin, the platelet aggregability induced by 2 micrograms/mL collagen and 5 and 10 mumol/L adenosine diphosphate decreased compared with aggregability before medication (P < .005), but the reductions had no significant correlation with the plasma fibrinogen concentration.

CONCLUSIONS

The relative antiaggregatory effect of ticlopidine is significantly decreased with higher plasma fibrinogen concentrations. This may explain, at least in part, the individual variation in the response to ticlopidine.

Alternatively spliced isoform of P-selectin is present in vivo as a soluble molecule

To demonstrate the presence of a soluble isoform of P-selectin predicted from cDNA sequencing (Johnston, G.I., Bliss, G.A., Newman, P.J., and McEver, R.P. (1990) J. Biol. Chem. 265, 21381-21385), we immunoisolated and compared structurally P-selectin from fresh frozen human plasma with that from washed intact platelets. Plasma P-selectin was reactive with rabbit antiserum to a synthesized peptide (residues 762-774 of mature P-selectin) but was significantly less reactive with antibody to a peptide (residues 747-760). In contrast, platelet P-selectin reacted with both antibodies. S-Pyridylethylated plasma P-selectin was fractionated by reversed phase-high performance liquid chromatography into two major species. From platelets, two virtually identical species were separated. Sequential digestion with Achromobacter protease I and then Staphylococcus V8 protease produced peptides assigned to the tail region of the protein including the putative spliced site. From the more hydrophilic species in both plasma and platelets, a peptide completely lacking the sequence of the putative spliced site was identified. In contrast, the more hydrophobic species yielded a peptide with an intact transmembrane sequence. Hence, these results provide direct evidence that the previously predicted soluble isoform of P-selectin is actually synthesized in vivo and is present as a circulating molecule.

Identification of beta-trace as prostaglandin D synthase

Human cerebrospinal fluid (CSF) is the richest source of prostaglandin (PG) D synthase, a key enzyme in sleep regulation, having a specific activity of 20-130 nmol/min/mg protein that is almost two orders of magnitude higher than that of crude rat brain homogenate (2-7 nmol/min/mg protein). PGD synthase was purified from human CSF approximately 8-fold to apparent homogeneity in a yield of 6% by ammonium sulfate fractionation followed by column chromatographies on phenyl-Sepharose and DEAE-cellulose. The purified enzyme displayed enzymatic properties almost identical to those of rat brain PGD synthase in terms of Mr, specific activity, optimum pH, Km value, and SH requirement. The purified PGD synthase cross-reacted with an antibody against rat brain PGD synthase and also with that against human beta-trace, a major protein in the CSF. Furthermore, beta-trace cross-reacted with rat brain PGD synthase antibody. The N-terminal sequences of human PGD synthase, beta-trace, and purified PGD synthase from human CSF were essentially identical. These results clearly show that beta-trace is structurally and enzymologically identical to PGD synthase.

Expression of an endogenous retroviral gene product in human placenta

To investigate the presence and potential pathophysiological role of endogenous retroviruses in humans, we prepared a recombinant protein using clone 4-I, a proviral sequence. DNA fragments containing the env region of clone 4-I were subcloned into a prokaryotic expression vector (pET3), and 2 fusion proteins, SU413 and SU415, were then expressed in Escherichia coli after treatment with isopropyl-beta-thiogalactopyranoside (IPTG). By sonicating lysates of the transformed E. coli, the recombinant protein SU413 was successfully separated from the native bacterial components, and was used to raise an antiserum in rabbits. In immunoblot analysis, this antiserum specifically recognized the recombinant protein, but did not react with other components of E. coli. This antiserum was then used for an immunofluorescence study of human placenta, in which the env gene transcript has been reported. As a result, the anti-SU413 serum detected substances in syncytiotrophoblasts and vascular endothelia from a human placenta. No such reactivity was detected in human kidney or human liver. Immunoblot analysis revealed that this antiserum reacted to a single molecule of 38-kDa in placenta, and its reactivity was reduced by the antiserum absorbed with SU413 antigen. These findings suggest that human placental syncytiotrophoblasts and vascular endothelia preferentially express a molecule encoded by human endogenous retrovirus clone 4-I.

Primary and higher order structures of nematode (Ascaris suum) mitochondrial tRNAs lacking either the T or D stem

By fractionation using polyacrylamide gel electrophoresis and/or a preparative hybrid selection method employing solid-phase DNA probes, we prepared and characterized mitochondrial tRNAs from the body wall muscle of Ascaris suum, all of which are thought to lack either the T stem or the D stem from their gene sequences (Okimoto, R., and Wolstenholme, D. R. (1990) EMBO J. 10, 3405-3411). Some of the partially purified tRNAs were appreciably aminoacylated with an extract of A. suum mitochondria. The three species sequenced had CCA sequence at their 3'-ends, and tRNA(Met) had 5-formylcytidine at the anticodon first position, a new modified nucleoside found at the same position of bovine mitochondrial tRNA(Met) (Moriya, J., Yokogawa, T., Wakita, K., Ueda, T., Nishikawa, K., Crain, P. F., Hashizume, T., Pomerantz, S. C., McCloskey, J. A., Kawai, G., Hayashi, N., Yokoyama, S., and Watanabe, K. (1994) Biochemistry 33, 2234-2239). Enzymatic probing of these tRNAs supported the secondary structural model proposed by Okimoto and Wolstenholme in the reference cited above. Chemical probing of tRNA(Phe) demonstrated the existence of tertiary interactions between the (T arm-variable loop)-replacement loop and the D arm. The results suggest that these tertiary interactions enable the bizarre tRNAs of nematode mitochondria to maintain an L-shape-like structure in order to function in the nematode mitochondrial translation system.

[Studies on auditory brainstem responses showing absence or significantly poor formation of waves II-V in children]

We performed a retrospective study on 7 children in whom the auditory brainstem responses (ABR) showed absence or significantly poor formation of waves II-V. Two patients had degenerative diseases that affected the brains diffusely. In the remaining 5 patients, the symptoms consisted of action tremor (3 patients) or pyramidal signs (2 patients). There were neither clinical signs nor neuroimaging findings suggesting brainstem involvements. The evolutional changes of the ABRs had a good correlation with the clinical course. Absence or significantly poor formation of waves II-V of ABR occurs in various diseases and may not necessarily reflect severe organic brain lesions.

[123I-MIBG myocardial scintigraphy in diabetic patients: association with autonomic neuropathy]

123I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy was performed in 20 diabetic patients (NIDDM) and 8 control subjects to investigate the association between clinical autonomic nerve dysfunction and myocardial accumulation of MIBG. We used coefficient variance of R-R interval (CVR-R) as a index of the autonomic neuropathy and categorized diabetes into two groups (CVR-R > or = 2.0: non-autonomic neuropathy. CVR-R < 2.0: autonomic neuropathy). In planar imaging studies, heart to mediastinum MIBG uptake ratio (H/M) was calculated on both early and delayed images. The washout ratio of 123I-MIBG in the heart (%WR) was also obtained using myocardial tracer activity on the both images. Mean value of these indices in diabetic group did not reveal any significant difference with the value in the control group. On the SPECT images, low uptake was observed in the posterior-inferior wall with normal uptake of 201Tl in diabetic patients with non-autonomic neuropathy. These areas extended in patients with autonomic neuropathy. The mean value of count ratio of posterior-interior to anterior wall (posterior-inferior/anterior ratio: PI/A) in the diabetic autonomic neuropathy group was significantly higher than in the control group on the both early and delayed images. And the mean value of regional %WR in the posterior-inferior wall calculated by the both MIBG SPECT images was significantly higher in the non-autonomic neuropathy group than in the control group. In the diabetic patients, retention mechanism of 123I-MIBG was considered to be involved at an early stage without autonomic nerve dysfunction clinically. As autonomic neuropathy progressed severely, uptake mechanism was also supposed to be involved. Therefore, 123I-MIBG myocardial scintigraphy was useful for early detection of cardiac sympathetic nervous dysfunction in diabetic patients.

Application of typing by pulsed-field gel electrophoresis to the study of Clostridium difficile in a neonatal intensive care unit

Pulsed-field gel electrophoresis (PFGE) analysis of restriction pattern polymorphism was applied to type Clostridium difficile isolated from neonates hospitalized in a neonatal intensive care unit, and the results were compared with those of immunoblot analysis. C. difficile was isolated from fecal specimens of 41 (61%) of 67 neonates during a 5-month investigation. All of these neonates were asymptomatic. Fifty-five C. difficile isolates from 32 patients were analyzed by PFGE after digestion with SmaI and SacII endonucleases and by immunoblotting with 10 different antisera. Fifty-three of 55 isolates from 30 patients were identical by PFGE analysis after SmaI and SacII digestion and immunoblot analysis. Two isolates were different from each other and from the epidemic group by both PFGE and immunoblot analysis. All 53 epidemic isolates were nontoxigenic, while the two remaining isolates were toxigenic. These results suggest that nosocomial spread of nontoxigenic C. difficile infection in the neonatal intensive care unit and suggest that both PFGE and immunoblot are powerful typing tools for the epidemiological study of C. difficile.

Primary malignant lymphoma of the penis: a case report

We report a rare case of primary malignant lymphoma of the penis developing a bulky scrotal mass. Tumor excision and radiotherapy were followed by abdominal recurrence. Salvage chemotherapy was unsuccessful and the patient died 9 months later.

[Imipenem/cilastatin sodium alone or combined with amikacin sulfate in respiratory infections]

In the present study, we used the envelope method to divide patients with respiratory infections into two groups: a monotherapy group given imipenem/cilastatin sodium (IPM/CS) and a combination therapy group given imipenem/cilastatin sodium plus amikacin sulfate (AMK). We then compared the clinical efficacy and safety between groups. 1. Safety was evaluated in 83 patients in the IPM/CS group and 88 in the IPM/CS + AMK group while clinical efficacy was evaluated in 77 and 80 patients in the respective groups. 2. The overall efficacy rate was 84.4% in the IPM/CS group. Among the main infections, the efficacy rates were 82.7% in 52 cases of pneumonia (including lung abscess), 100% in cases of infected bronchiectasis, 66.7% in six cases of secondary infection of chronic respiratory disease, and 100% in four cases of chronic bronchitis. The overall efficacy rate was 83.8% in the IPM/CS + AMK group. Among the main infections, the efficacy rates were 88.1% in 59 cases of pneumonia (including lung abscess), 83.3% in 12 cases of infected bronchiectasis, and 60.0% in five cases of secondary infection of chronic respiratory disease. No significant differences in efficacies were seen between groups. 3. In the IPM/CS group, the efficacy rates were 92.3% for patients without prior antibiotic therapy in the IPM/CS group and 68.0% for those with prior therapy; in the IPM/CS + AMK group, the respective rates were 83.7% and 83.9%. In the IPM/CS group, there was a significant difference in the responses of patients with and without prior antibiotic therapy (P < 0.05). 4. Side effects were observed in six patients in the IPM/CS group (7.2%) and two patients in the IPM/CS + AMK group (2.3%). Abnormal laboratory test results were noted in 5 patients in the IPM/CS group (6.0%) and in 10 in the IPM/CS + f1p4group (11.4%). There was no significant difference in the incidence of side effects between groups and no severe adverse reactions in either group. These results indicate that IPM/CS alone produces of good response in moderate to severe respiratory infections while IPM/CS combined with AMK is useful in intractable respiratory infections.

Huge sellar chordoma: CT demonstration

The authors report the computed tomographic (CT) findings in a patient with an unusual large intracranial chordoma involving the midline sellar region. This rare intracranial tumor is reviewed in the literature, and in particular the values of CT evaluations are detailed in the presented case with a special reference to differential diagnosis of the tumors in and around the sella turcica.

A novel hypothyroid 'growth-retarded' mouse derived from Snell's dwarf mouse

This paper describes a novel mutant mouse that has been spontaneously derived from the Snell's dwarf (DW/J) mouse. It was named the 'growth-retarded mouse' because of a characteristic growth pause followed by the delayed onset of pubertal growth. The onset of the increase in pituitary GH content that normally occurs concomitant with pubertal growth was also delayed in the growth-retarded mice. The serum concentration of thyroxine was very low in these mice from the neonatal period through adulthood, and a supplement of tri-iodothyronine was effective in shortening the growth pause and commencing the suppressed pubertal growth. Histological and immunohistochemical studies revealed that the anterior pituitary gland of the growth-retarded mouse contains clustered unusual chromophobic cells which are not reactive to various antisera against anterior pituitary hormones and the gland becomes enlarged with age. Breeding data indicated that these characteristics of the mice show an autosomal recessive inheritance and the gene responsible was designated as 'grm'. Partial linkage analysis utilizing microsatellite polymorphism demonstrated that the grm gene does not identify with the lit or hyt genes. Based on comparison of the hormonal status and growth pattern between growth-retarded, dwarf and normal mice, we have suggested the existence of a mutual interaction, possibly positive feedback regulation, between the pituitary and thyroid glands, that develops or matures the hormonal network which is responsible for rapid somatic growth and metabolic changes at puberty in mice.