The ubiquitin–proteasome system regulates p53-mediated transcription at p21waf1 promoter

The ubiquitin (Ub)-proteasome system (UPS) promotes the proteasomal degradation of target proteins by decorating them with Ub labels. Emerging evidence indicates a role of UPS in regulating gene transcription. In this study, we provided evidence for the involvement of UPS in the transcriptional activation function of tumor suppressor p53. We showed that both ubiquitylation and proteasomal functions are required for efficient transcription mediated by p53. Disruption of transcription by actinomycin D, 5,6-dichloro-1-beta-D-ribofuranosyl-benzimadazole or alpha-amanitin leads to accumulation of cellular p53 protein. Proteasome inhibition by MG132 increases the occupancy of p53 protein at p53-responsive p21(waf1) promoter. In addition, the Sug-1 component of 19S proteasome physically interacts with p53 in vitro and in vivo. Moreover, in response to ultraviolet-induced DNA damage, both the 19S proteasomal components, Sug1 and S1, are recruited to p21(waf1) promoter region in a kinetic pattern similar to that of p53. These results suggested that UPS positively regulates p53-mediated transcription at p21(waf1) promoter.

Turbulence of glomerular hemodynamics involved in progressive glomerulosclerosis

There is increasing evidence that changes of glomerular hemodynamics or glomerular growth responses may promote the development of glomerulosclerosis. Major problems retarding research progress include lack of suitable experimental animal models, with the exception of the ablation model, and the need for in vivo real-time analysis of glomerular hemodynamics. This study examined the sequence of pathological changes from the viewpoints of microcirculation and histopathology, from the acute stage to the chronic course and the final stage of glomerulosclerosis, using the confocal laser scanning microscope system. There is a marked difference in prognosis between sham-operated (two-kidney) and nephrectomized (one-kidney) rats after injection with anti-Thy-1 antibody. The former reversibly returns to normal and the latter irreversibly go to progressive sclerosis, respectively. The turning point determining the progression of glomerulosclerosis in both groups seemed to be the period from 7 to 14 days after disease induction, when disturbance of local intraglomerular blood flow continued in the one-kidney groups. In conclusion, this study provides the first hemodynamic-based evidence showing that disturbance of intraglomerular microcirculation is a critical marker for progressive glomerulosclerosis.

Signal and noise transfer properties of photoelectric interactions in diagnostic x-ray imaging detectors

Image quality in diagnostic x-ray imaging is ultimately limited by the statistical properties governing how, and where, x-ray energy is deposited in a detector. This in turn depends on the physics of the underlying x-ray interactions. In the diagnostic energy range (10-100 keV), most of the energy deposited in a detector is through photoelectric interactions. We present a theoretical model of the photoelectric effect that specifically addresses the statistical nature of energy absorption by photoelectrons, K and L characteristic x rays, and Auger electrons. A cascaded-systems approach is used that employs a complex structure of parallel cascades to describe signal and noise transfer through the photoelectric effect in terms of the modulation transfer function, Wiener noise power spectrum, and detective quantum efficiency (DQE). The model was evaluated by comparing results with Monte Carlo calculations for x-ray converters based on amorphous selenium (a-Se) and lead (Pb), representing both low and high-Z materials. When electron transport considerations can be neglected, excellent agreement (within 3%) is obtained for each metric over the entire diagnostic energy range in both a-Se and Pb detectors up to 30 cycles/mm, the highest frequency tested. The cascaded model overstates the DQE when the electron range cannot be ignored. This occurs at approximately two cycles/mm in a-Se at an incident photon energy of 80 keV, whereas in Pb, excellent agreement is obtained for the DQE over the entire diagnostic energy range. However, within the context of mammography (20 keV) and micro-computed tomography (40 keV), the effects of electron transport on the DQE are negligible compared to fluorescence reabsorption, which can lead to decreases of up to 30% and 20% in a-Se and Pb, respectively, at 20 keV; and 10% and 5%, respectively, at 40 keV. It is shown that when Swank noise is identified in a Fourier model, the Swank factor must be frequency dependent. This factor decreases quickly with frequency, and in the case of a-Se and Pb, decreases by up to a factor of 3 at five cycles/mm immediately above the K edge. The frequency-dependent Swank factor is also equivalent to what we call the "photoelectric DQE," which describes signal and noise transfer through photoelectric interactions.

Antepartum immunoprophylaxis of three doses of hepatitis B immunoglobulin is not effective: a single-centre randomized study

To investigate the efficacy of antepartum administration of three doses of hepatitis B immunoglobulin (HBIg), currently being used in China, 250 pregnant women who were seropositive for hepatitis B e antigen (HBeAg) were randomly divided into study (117 cases) and control groups (133 cases). Subjects in the study group received HBIg 400 IU intramuscularly once a month at the third, second and first month before delivery; subjects in the control group received no antepartum treatment. All neonates received passive-active immunization after birth. The maternal hepatitis B virus (HBV) markers, hepatitis B surface antigen (HBsAg) titres and HBV deoxyribonucleic acid (DNA) levels were measured at week 28 of gestation (before the antepartum treatment) and at labour; the neonatal serum HBV markers were detected at birth and at 12 months after birth. No side-effects were found in any of the women or their neonates. No statistical differences were seen between the maternal HBsAg and HBV DNA levels of the study and control groups at labour nor the protective efficacy rates of postnatal immunoprophylaxis at 12 months after birth (P > 0.05, respectively). To conclude, antepartum administration of three doses of HBIg for the HBeAg-positive women is inefficacious.

Screening and identification of substances that regulate nephrin gene expression using engineered reporter podocytes

Downregulation of nephrin in podocytes leads to development of proteinuria in human and experimental kidney diseases. However, little is understood about pathophysiologic substances that regulate nephrin expression. In this report, we established conditionally immortalized reporter podocytes REPON for sensitive, continuous monitoring of nephrin gene expression. A murine podocyte cell line harboring a temperature-sensitive simian virus 40 large T antigen was stably transfected with a gene encoding secreted alkaline phosphatase (SEAP) under the control of the 5.4 or 8.3 kb nephrin gene promoter. The established reporter cells REPON5.4 and REPON8.3 were exposed to various pathophysiologic substances, and culture media were subjected to SEAP assay to identify regulators of nephrin gene expression. Among the bioactive substances tested, three physiological ligands of nuclear receptors including all-trans-retinoic acid, 1,25-dihydroxyvitamin D3, and dexamethasone significantly activated the nephrin gene promoter in a dose-dependent manner. These effects were observed in both REPON5.4 and REPON8.3 and were associated with upregulation of nephrin mRNA. The effects of these substances were synergistic, and the maximum effect was observed by combination of three agents. In contrast, inflammatory cytokines interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha as well as phorbol ester significantly downregulated the activity of the nephrin promoter as well as nephrin gene expression. These results elucidated the bidirectional regulation of nephrin by distinct pathophysiologic substances and may provide molecular bases for explaining how proteinuria is induced under pathologic situations and why some ligands for nuclear receptors have the anti-proteinuric potential.

Treatment of HIV positive anal cancer patients with chemoradiation

4154

Background: Tolerance and outcomes of HIV+ anal cancer patients are questioned, especially since the emergence of High Active Anti-Retroviral Therapy (HAART) in the mid-1990s. Our experience in treating these patients before and during the HAART era is reported. Methods: From 1987–2003, 19 HIV+ invasive anal cancer patients were treated with: 30–60 Gy pelvic RT (2 Gy/d) + Mitomycin C (10 mg/m2 bolus on d1) + 5-FU (1000 mg/m2/d, continuous infusion d1–4 and 28–31). Results: Mean CD-4 count at cancer diagnosis was 311, with 9 on HAART. Mean CD-4 count for HAART was 383 and 247 for non-HAART. Stage distribution: 1 T1, 9 T2, 9 T3, 18 N0, 1 N3. Mean f/u was 40 months. 79% had complete response after chemoRT. 4 had locally persistent disease. There was 1 loco-regional recurrence and 2 distant metastases. 79% of the cohort is colostomy-free. Median OS has not been reached. OS at 2 and 3 years were: 88%and 79%, with 10 Alive and NED, 1 Alive with disease, 3 Dead of disease, 5 Dead from intercurrent disease (all secondary to AIDS). 1.5 year DFS was 74%. Break and CD-4 count < 200 had a statistically significant negative impact on DFS, but not OS. HAART did not affect either factor. 11 had RT break for median of 17 days. There was no Grade 4 skin toxicity. All completed the 2nd 5-FU cycle: 7 had delay (median 7 days) and 3 had dose decrease. There were 6 hospitalizations: 5 neutropenic fevers and 1 perineal abscess rupture. WBC Toxicity: 6-Grade 3 and 2-Grade 4. Platelet Toxicity: 2-Grade 3. Heme toxicity was not affected by HAART or CD4 count < 200. There were no treatment related deaths. Conclusion: HIV+ anal cancer patients have reasonable tolerance and outcomes with chemoRT. CD-4 count < 200 and break were negative prognostic factors for DFS. Our 79% colostomy free survival is similar to RTOG 9208, where suboptimal control was attributed to mandatory RT break. Factors influencing break include heme and skin toxicity. To improve the therapeutic ratio, substitution of Mitomycin-C with Cisplatin, IMRT, and Ethyol are being explored.

No significant financial relationships to disclose.

Phase I study of the safety and efficacy of atiprimod, a novel azaspirine, for patients with advanced cancer

13050

Background: Atiprimod (N-N-diethl-8,8-dipropyl-2-azaspiro [4.5] decane-2-propanamine) is an oral cationic azaspirane that suppresses angiogenesis by inhibiting both bFGF and VEGF induced proliferation and migration. Atiprimod has been shown to down-regulate multiple growth factors involved in tumor progressions and metastases, including IL-6, TNF-α, and VEGF. Methods: This is an ongoing, single-center, open-label, ascending dose (modified Fibonacci) Phase I trial of oral atiprimod in patients with advanced cancers (3+3 design). Atiprimod was given orally for 14 days every 28-day cycle. The primary objectives are to identify the MTD and to evaluate the safety of atiprimod; the secondary objectives include measuring PK and describing efficacy. Data from these patients enrolled are presented here. Results: Fourteen patients have been treated to date with 60 mg tablets (N = 3), 60 mg capsules (N = 3), 90 mg capsules (N = 3) and 120 mg capsules (N = 5). The most common side effects, which occurred in over half the patients, were related to the gastrointestinal system, and include nausea (11), diarrhea (7), vomiting (4) abdominal pain (2) and dyspepsia (2). These events were generally low-grade, occurred primarily during days of active drug administration and tended to resolve during off-drug days. Less common adverse events were sinus headaches, and elevated serum transaminases, alkaline phosphatase and creatinine. One patient who received prolonged therapy (7 months) developed fever and multi-organ failure of unclear etiology. One patient with uterine leiomyosarcoma experienced a DLT (syncope and hypotension) at 120 mg/day, and that dose level is therefore being expanded up to 6 patients. One patient with midgut carcinoid tumor and liver metastasis achieved a partial remission lasting 2+ months (50% decrease in maximum diameter by RECIST). Three patients (carcinoid = 2 and thymoma = 1) had stable disease for four, four and six months, respectively. Conclusions: Preliminary data indicate that atiprimod was reasonably tolerated, with predominantly gastrointestinal side effects. There is early evidence of anti-tumor activity in carcinoid tumors. Dose escalation continues.

[Table: see text]

Phase I/II trial of capecitabine (C), dacarbazine (D) and imatinib (I) (CDI) for patients (pts) metastatic medullary thyroid carcinomas (MTC)

13048

Background: MTC is a rare tumor that responds poorly to conventional chemotherapy. 5-FU and D are frequently used, with an expected response rate of around 15%. MTC is often associated with multiple endocrine neoplasia type 2, an autosomal dominant syndrome caused by a mutation in the RET proto-oncogene which encodes RET, a tyrosine kinase receptor. I is a tyrosine kinase inhibitor with activity against c-Kit, PDGF and possibly RET, and we postulated that its addition to chemotherapy would increase its efficacy against this disease. Methods: We designed a phase I/II trial combining escalating doses of oral C, IV D and oral I. Pts with any advanced solid tumors were eligible for the phase I part of the trial. Results: 13 pts were entered and 12 were eligible (7 MTC, 2 adrenocortical, 1 islet-cell, 1 insular thyroid and 1 small cell). 4 pts did not complete one cycle (1 pt withdrew after 5 days and 2 pts progressed in less than 10 days and were replaced for toxicity analysis, 1 had a DLT and is included). 3 patients were entered in dose level 1, without DLT. 2 out of 6 pts developed DLT at the second dose level (1 G 3 fatigue and 1 G3 hypokalemia). Three additional pts are being entered on dose level 1. The first one had PD after 7 days and is being replaced. For the 11 pts who were evaluable, best response was 3 SD (range 3 to 9 + months) and 8 PD. Conclusions: The combination of CDI is feasible but has resulted in an unexpected pattern of toxicity in this patient population, with fatigue and hypokalemia as the DLT. No significant diarrhea or hand-foot syndrome was seen. Only G1 and 2 fluid retention and neutropenia have been encountered. Only minor reduction in tumor size has been seen among these heavily pretreated pts. Once the phase I is complete, the trial will continue in a phase II setting for untreated MTC pts.

[Table: see text]

[Table: see text]

Cellular localization of thrombin in prostate: Implications for thrombin targeted therapy in prostate cancer

14527

Background: Tumor and coagulation interaction is complex and heterogeneous. Expression of an intact repertoire of coagulation proteins is not detected in all tumor types. Thrombin, a key coagulation protein, which has been observed to promote tumorigenesis in experimental models, is not expressed on breast, colon and squamous lung cancer cells, but has been detected on small cell lung, melanoma and renal cancer epithelium. In prostate cancer, expression of its receptor, protease activated receptor-1 (PAR-1) has been previously reported but thrombin expression on epithelium not determined. Therefore, we evaluated thrombin and prothrombin expression in prostate specimens. Methods: Quantitative real-time PCR was performed for (pro)thrombin mRNA expression in fresh prostate cancer tissue lysates obtained from localized disease (n = 9 prostatectomy specimens) and advanced disease (n = 7 channel trans-urethral prostate resection specimens). Prothrombin and thrombin protein immunohistochemistry was performed on anonymized prostate tissue micro arrays which included benign (n = 117), prostate intra-epithelial neoplasia (PIN; n = 26) and prostate cancer (n = 112) cores. Results: (Pro)thrombin mRNA expression (normalized to 18s mRNA) was detected in all cancer tissue lysates. Mean intensity of expression in advanced cancer specimens was 20.3 compared to 14.0 for local stage specimens (p = 0.09; Wilcoxon rank sum test). Spatially, expression of thrombin was detected in stroma, benign and malignant epithelium (see Table) and on vascular endothelium. Prothrombin localization was similar to thrombin expression. Conclusions: Thrombin’s tumorigenic effects via PAR-1 activation provide novel therapeutic targets in tumors expressing thrombin-PAR1 axis. The current study confirms thrombin expression on prostate epithelium and taken with previous results of PAR1 epithelial expression, provides a rationale for exploring specific thrombin inhibitors and/or PAR inhibitors in prostate cancer. [Table: see text]

No significant financial relationships to disclose.

Studies on the growth metabolism of Bacillus thuringiensis and its vegetative insecticidal protein engineered strains by microcalorimetry

The metabolic power-times curves of Bacillus thuringiensis and its vegetative insecticidal protein engineered strains were determined at 30 degrees C by using a thermal activity monitor air Isothermal Microcalorimeter, ampoule method. From the power-times curves, the maximum power (Pmax) in the log phase, the growth rate constant (k), the generation times (tG), the time of the maximum power (tmax), the heat effects (Qlog) for log phase, and the total heat effect in 45 h (Qtotal) of B. thuringiensis strains can be obtained. The results indicate that their power-times curves are different. The relationship between their metabolic power-times curves and character of bacteria metabolism, and thermokinetics and gene expression were analyzed and discussed. The character of the bacteria power-times curves reflected the physiologic character of gene expression. The microcalorimetric method proved to be a reliable and sensitive tool for the assessment of the growth metabolism, the heat output in bacteria and its engineered strains. The determination of the thermokinetic character is beneficial to the control of fermentation.

Identification of a novel gill-specific calpain from rainbow trout (Oncorhynchus mykiss)

Calpains are calcium-dependent neutral proteases responsible for many cellular functions. The two forms of calpain ubiquitously expressed in mammalian tissues are known as mu-calpain and m-calpain. We report here the identification of a novel calpain that is similar to but distinct from the mu- and m-calpains in rainbow trout. The cDNA of the novel gene is 2623 bp in length with a single open reading frame. The predicted protein (676 amino acids) contains the conserved calpain characteristic domains that include: domain I (pro peptide), II (cysteine catalytic site), III (electrostatic switch), and IV (calmodulin-like) with five Ca(2+)-binding EF hands. Northern blot and RT-PCR analyses demonstrated that the novel calpain gene is predominantly expressed in rainbow trout gills. Comparison of the novel protein with the ubiquitously expressed calpains and several mammalian tissue-specific calpains revealed that the novel calpain is an orthologue of the mammalian digestive tract specific calpain (calpain 9).

242 POST-TRANSCRIPTIONAL REGULATION OF JY-1 mRNA ABUNDANCE DURING THE BOVINE OOCYTE-TO-EMBRYO TRANSITION

Oocyte-expressed genes play key roles in folliculogenesis and early embryonic development. The function of JY-1, a novel gene specifically expressed in bovine oocytes and early embryos, is unknown. We previously reported the expression pattern of JY-1 mRNA during meiotic maturation and early embryogenesis. The objective of this study was to elucidate the post-transcriptional regulation of JY-1 mRNA during oocyte maturation and early embryogenesis. For investigation of changes in length of JY-1 transcripts during the oocyte-to-embryo transition, total RNA isolated from germinal vesicle (GV) oocytes, metaphase II (MII) oocytes, and pronucleus (PN) stage embryos (300 oocytes/embryos per time point) was subjected to Northern blot analysis. Three major JY-1 transcripts of different length (approximately 1.8 kb, 1.2 kb, and 700 bp) were detected in GV oocytes. The size of all transcripts was decreased at MII, and PN stages by approximately 100 to 200 bp. The intermediate sized transcript was predominant at GV, MII and PN stages. Based on these initial qualitative results focused solely on changes in transcript size, we then conducted more detailed quantitative studies (using real-time PCR) focused on characterization of temporal changes in abundance of polyadenylated versus total JY-1 transcripts during early development. Total RNA samples isolated from GV and MII oocytes and from embryos at PN, 2-cell, 4-cell, 8-cell, 16-cell, morula, and blastocyst stage (n = 5 pools of 10 oocytes/embryos per time point) were divided into two equal aliquots. One aliquot was reverse transcribed into cDNA with oligo dT primers for quantification of polyadenylated transcripts and the other aliquot was transcribed with random hexamers (RH) for quantification of total transcripts. Amounts of polyadenylated JY-1 mRNA decreased during meiotic maturation (P < 0.0001), were increased (P < 0.05) at the PN and 4-cell stages relative to the MII stage, and then decreased to nearly undetectable levels after the 16-cell stage of embryo development. In contrast, amount of total JY-1 transcripts gradually decreased from PN through 16-cell stages to nearly undetectable levels thereafter. To confirm that the up-regulation of polyadenylated JY-1 mRNA in early developing embryos was not due to de novo transcription, alpha-amanitin was used to block the RNA polymerase II enzyme during the window of the first (24-13 h post-fertilization) or the second (33-14 h post-fertilization) embryonic cell cycle, and embryos at the 2-cell and 4-cell stages were collected (n = 4 pools of 10 embryos per time point). No significant changes were observed in abundance of JY-1 mRNA in control versus alpha-amanitin treated embryos. We conclude that JY-1 transcripts decrease in length during meiotic maturation and that polyadenylated JY-1 mRNAs detected in early developing embryos are oocyte-derived and not due to de novo transcription in early embryos. This work was supported by the Rackham Foundation and the Michigan Agricultural Experiment Station.

Enhancement of NF-kappaB activity by resveratrol in cytokine-exposed mesangial cells

Resveratrol, a natural polyphenolic phytoalexin, has been considered as a potential anti-inflammatory agent because of its suppressive effect on nuclear factor-kappaB (NF-kappaB). However, we recently found that treatment of glomerular mesangial cells with resveratrol significantly and dose-dependently enhanced NF-kappaB activation triggered by proinflammatory cytokines. This finding was evidenced by different reporter assays as well as by expression of an endogenous NF-kappaB-dependent gene, intercellular adhesion molecule-1. The NF-kappaB promoting effect of resveratrol was also observed in renal tubular LLCPK1 cells, but not in HepG2 hepatoma cells. In all cell types tested, treatment with resveratrol alone did not affect NF-kappaB activity. The enhanced activation of NF-kappaB by resveratrol progressed for at least 24 h and was accompanied by sustained down-regulation of an endogenous NF-kappaB inhibitor, IkappaBbeta, but not IkappaBalpha. Although expression of inducible nitric oxide synthase was suppressed by resveratrol, nitric oxide, a negative regulator of NF-kappaB, was not involved in the regulation of NF-kappaB by resveratrol. These data elucidated, for the first time, that resveratrol may enhance activation of NF-kappaB under certain circumstances.

Characterization and comparison of microsatellites derived from repeat-enriched libraries and expressed sequence tags

The construction of high-density linkage maps for use in identifying loci underlying important traits requires the development of large numbers of polymorphic genetic markers spanning the entire genome at regularly spaced intervals. As part of our efforts to develop markers for rainbow trout (Oncorhynchus mykiss), we performed a comparison of allelic variation between microsatellite markers developed from expressed sequence tag (EST) data and anonymous markers identified from repeat-enriched libraries constructed from genomic DNA. A subset of 70 markers (37 from EST databases and 33 from repeat enriched libraries) was characterized with respect to polymorphism information content (PIC), number of alleles, repeat number, locus duplication within the genome and ability to amplify in other salmonid species. Higher PIC was detected in dinucleotide microsatellites derived from ESTs than anonymous markers (72.7% vs. 54.0%). In contrast, dinucleotide repeat numbers were higher for anonymous microsatellites than for EST derived microsatellites (27.4 vs.18.1). A higher rate of cross-species amplification was observed for EST microsatellites. Approximately half of each marker type was duplicated within the genome. Unlike single-copy markers, amplification of duplicated microsatellites in other salmonids was not correlated to phylogenetic distance. Genomic microsatellites proved more useful than EST derived microsatellites in discriminating among the salmonids. In total, 428 microsatellite markers were developed in this study for mapping and population genetic studies in rainbow trout.

Changes in Chemical Composition of Alxa Bactrian Camel Milk During Lactation

Changes in chemical composition of Alxa bactrian camels reared in Inner Mongolia (China) during lactation were investigated. Colostrum and milk samples from 10 nomadic female camels in their first season of lactation were collected periodically from parturition until 90 d postpartum (PP). The average contents of gross composition were 14.23% protein, 4.44% lactose, 0.27% fat, 0.77% ash, and 20.16% total solids in colostrum at 2 h PP, and the respective mean values were 3.55, 4.24, 5.65, 0.87, and 14.31% for regular milk on d 90. A 15-fold increase was shown in fat content during the first 24 h, whereas a sharp decrease was shown during the first 12 h of lactation in protein, ash, and total solids contents. Variation in lactose content was small (4.24 to 4.71%) throughout the study period. Total N, nonprotein N, casein N, and whey protein N were found to be 2.23, 0.06, 0.86, and 1.31 g/100 mL for the colostrum at 2 h PP; and 0.56, 0.04, 0.45, and 0.07 g/100 mL for the milk at 90 d PP. Percentages of caseins increased steadily, whereas whey proteins declined gradually until 3 mo of lactation. Gas liquid chromatography analysis of milk fat showed that the content of even-numbered saturated fatty acids (C12:0-C18:0) in camel colostrum (2 h to 7 d PP) was lower than that of regular milk (15 to 90 d PP). The predominant saturated fatty acids were C14:0, C16:0, and C18:0, regardless of the stage of lactation. There was a considerable level of polyunsaturated fatty acids (mainly C18:1) in Alxa camel's milk fat. The levels of Ca, P, Na, K, and Cl were 222.58, 153.74, 65.0, 136.5, and 141.1 mg/100 g, respectively, at 2 h PP; the values of the minerals were 154.57, 116.82, 72.0, 191.0, and 152.0 mg/100 g, respectively, for the regular milk on d 90. The levels of vitamins A, C, E, B1, B2, B6, and D were 0.97, 29.60, 1.45, 0.12, 1.24, 0.54 mg/L, and 640 IU/L, respectively, in Alxa camel milk at 90 d PP. Vitamin A and C contents were higher and vitamins E and B1 were lower than those in colostrum. Sodium dodecyl sulfate-PAGE and densitometry results demonstrated that Alxa camel colostrum is rich in immunoglobulins, serum albumin, and 2 unknown fractions, which are reduced in amount (%) within 2 d of lactation. It seems that there is lack of beta-lactoglobulin in Alxa camel milk, whereas casein and -lactalbumin start at a low level and increase gradually until they reach their regular levels in the milk.